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ElkNut1

I don't know enough about the rest of your set up, but the number one priority in my opinion is having an accurate well tuned arrow. If the arrow is flying straight and true, and the broadhead is solid and as sharp as possible, and you are confident you will hit where you are aiming, then I'd say you are good.

Having said that... If you have room in the arrow spine range, a 125 grain head would only make things better. 30.25" is a very long arrow shaft. If your draw length is really that long, and if you are shooting around 70#, then you may not be able to switch to 125 grains without going to a 300 spine arrow.

30.25", good gawd! What is your actual draw length? Guys like you can get 300fps out of a 60lb 1984 bear whitetail.

IMO ......FOC is the most over rated criteria when setting up an arrow....especially when it comes to setting up for very high 30% FOC.

You are in the easton recommended range [and the range of what all of the pros use] with either setup- all good.

There are just so many variables in archery, from the type of bow you shoot, the poundage it's set at, to the arrow length, arrow weight, arrow diameter, etc., etc., that it really boils down to what works best for you. Shooting a high poundage bow, maybe FOC is not critical, but shooting a lower poundage bow, maybe FOC could be the difference between a dead animal and a wounded animal?

She is shooting on a smaller scale than you obviously so her results will be exponential vs yours, kinda like that guy's video w/ the straws. What she sees at 17yds you won't see until 40-50+ in regards to accuracy, but you will start to lose the benefit of a flatter trajectory. This means little if you only shoot to 30 maybe 40yds, beyond that is where the weight will take its toll. You will see increased penetration but that is expected.

I have some axis that I had 50gr brass in and I dang near ripped my shoulder out pulling those arrows. Good god they were hammers though.

I'm looking forward to your findings!

oh my goodness....you really typed that?

ElkNut1

She was shooting pretty light arrows before. I was preaching 'speed' to her. "You aren't shooting but 42lbs girl, we need to get you a light arrow for speed. Speed means penetration!" Well, I was wrong. So we did the experiment with those weed eater and nail arrows. It was enough to get me to investigate further. We switched her from ICS Hunter 500 to ICS Hunter 400. Moved up from the 100 grain head to the 125. Now we'll experiment with the inserts. Another trick I saw on YouTube, hey, it looked like it will work, is a guy used braided nylon rope instead of arrow tubes. He said it adds about 124 grains to his shaft. I figured it was worth a shot, rope is cheap.

As far as accuracy and distance. We didn't have time to go out to my range, so we shot in the driveway for that initial testing last week and 17 yards was about all the room we had to work with. Plus she is ranged in at 20 yards based up our blind setup. But even still, I was surprised there was no drop in elevation, even at that short distance.

I just ordered her some Carbon Express PileDriver Extreme Pass Throughs in the 250 shaft size, which is what Carbon Express recommended for her over the phone.

Once those shafts come in, we'll do a more comprehensive set of testing. Two things I want to track is the arrow weight of each arrow set up and it's FOC %. Then average out the penetration results. I have three targets. One field tip bag is was purchased in October, so it's practically in new condition. Not shot up to bad. The second is another field tip target and she shot it for the first time last week. The last one is a broadhead target that I just bought and we've never shot into it. Telling you this so you'll know we aren't shooting up worn out targets that have been sitting in the rain and sun for months. I keep all of mine in the workshop when not in use. Once we get the results in, I'll post them.

I didn't intend on taking over Trax's thread as he has a valid question in regards to his elk hunt. Trax, wish you well on the hunt and look forward to seeing the pictures when you get back.

Show me ONE MONEY SHOOTER in 3d, FITA or Target where accuracy is their bread and butter that drinks the EFOC Koolaid. Hmmm, there are none.

If it were an advantage, the money shooters would be all over it. Even the trad guys winning big tourneys don't go crazy with their FOC.

Elknut1, I understand where your coming from with limb storage but you are too low on your numbers before diminishing returns. With 70# limbs backed off to 65#'s my 600 grain arrow out penetrates my 455 grains arrows, this is with field points in a Rhino target. It wasn't until I was over 650 grains that my penetration was the same at which point I backed off.

As for accuracy and forgiveness with FOC, you guys are crazy not to take serious look at it for hunting situation with both accuracy and penetration. I can cut through a side wind and hit my mark at 50 yards.I have very little helicoil on my fletches because of FOC so I have less drag slowing my arrow at longer distances. Yes the drop is more than a 400 grain arrow which is why I have sights and a range finder.

In this photo the 420 grain arrow with a 192 grain total head weight wins. The 775 grain, 645 grain & 420 grain with 117 grain head weight all lagged behind.

ElkNut1

Between the two photos of a 518 grain arrow & a 645 grain arrow not able to out penetrate the 420 192 head weight I seriously doubt the 600 grain arrow will do any better. Thanks!

As a sidnote so there's no misunderstanding everyone of these arrow combos will kill elk! I shoot the 420 grain arrow with the 192 grain head/insert weight because it's a great balance of penetration, speed & accuracy for me.

ElkNut1

Ohio, I'm an elk hunter first & foremost, I started doing these tests many years ago because I'd read as many here do about heavier will ALWAYS out penetrate lighter out of the same bow weight. It did not make sense to me so I decided to test things out. I like using what works for me, if others want to do it they sure can do tests like I am. It helps give me confidence in my setup during my elk hunts.

No ballistics gel test in my future! (grin) I did just screw two sheets of plywood together for a 1-3/8" thickness with no back stop, now this is where some true penetration can shine! (grin) We shot at 25 yards & 41 yards. Penetrating that at 41 yards will not have you under gunned on your elk hunts no matter what reasonable distance you shoot! (grin)

ElkNut1

Its relevance is the consistency, but at the same time a brick wall is poor medium. Most tests are done on inconsistent medium or inadequate medium for proper illustration. We all know the naysayers will find any excuse, eliminating the excuses is executed via minimizing variables.

The issue lies when a particular test does not agree with ones hopes! So best thing is to go in with an open mind at let the cards fall where they may! (grin)

ElkNut1

That is yet another reason the Ashby reports are so valid. The medium was fresh animals, (the same medium that we are so interested in penetrating), but yet so big that it could not be fully penetrated and penetration could be measured.

The biggest problem with it is that bowsiters cannot duplicate it in their backyards, therefore it doesn't carry quite as much weight.

That being said, yes, a bag of marbles compared to compressed styrofoam is a bad comparison. You need to use a little common sense to choose a good target to conduct your test. I agree, plywood/OSB is as good as anything else.

Sapcut, fair enough sir! What arrow weight would you like me to test against the 420 grain arrow that does well out of my 66# bow & at what distance? (elk hunting distance) I will screw layers of plywood/osb together until only one arrow penetrates whatever that thickness ends up being. This way the shaft does not come into play.

I'm using the 420 grain arrow because it's what my limbs cast the best, anything heavier & penetration decreases. Thanks!

ElkNut1

Thats why I always bring up ballistic gel, its designed for this exact style of testing. Surely someone around here has some connections for this stuff, I'd imagine a high school science teacher should be able to get some.

You're in a contest to win $1,000,000. Whomever can sink an arrow the deepest into the rib cage of a fresh killed elephant with a broadside shot wins the jack. Two contestants. All equipment is exact, Everything is exact between the two...except arrow weight. 60# bow and two arrows to choose from.

One arrow is 400 grains, one is 600 grains and you get first pick. Which arrow are you going to choose to get that arrow deeper than your opponent.

And because your going to try thinking of something....EVERYTHING IS EQUAL OTHER THAN ARROW WEIGHT.

Im sorry but the "animal" argument is purely wrong for the purposes of testing. Anyone who has done anything remotely concerning the scientific method will tell you you are wrong.

Lets say both shoot it in the guts, but one guy hits a turd and the other misses all debris? How is that remotely comparable? have you seen an elephant TURD! Its like a softball only bigger.

To get back to your original question, I prefer a little higher FOC. Is it necessary in the grand scheme of things, probably not. There are many arguements (as in discussions, not bickering) about higher mass forward of center (balance point). There are advantages, none of them detrimental.

My setup is 400 grs at 305 fps and 16% FOC. No issues punching through elk at 30 yds.

I can testify to the targets being inconsistent in there density. She shot into the brand new target the other day, aiming at the different circles (5) and we found that the same arrow when fired into each circle penetrated to different depths. Which leads me to believe that the bag target, while brand new, is packed with a dense material but the density varies throughout the target. This is why I will average out the depths based over 4 or 5 shots with each arrow setup. Perfect science? No, but it will serve its purpose and be fun to do in the process. Good father/daughter bonding time flinging sticks downrange. :)

ElkNut1

Bushwhacker, right on sir! Time well spent!

ElkNut1

It's not. When testing your arrows, you don't hit both. You choose to hit one or the other at a time. If you don't then you just missed. Shoot again.

"You said yourself when the arrow exits the medium (plywood at the time) the test is null and void, how does exiting an animal any different?"

Exiting an animal is not any different. If you'll notice I mentioned the benefits of test shooting the large fresh animals...----> "The medium was fresh animals, (the same medium that we are so interested in penetrating), but yet so big that it could not be fully penetrated and penetration could be measured."

What I try to keep in mind is that my goal (main reason I'm on bowsite rather than LW) is to find the best arrow build for my bow that will give me the best chance of penetrating....a big animal. Any and all it parts. I care not for penetrating any other medium. Totally irrelevant.

I personally think that I have the best I can find but always looking for a better killer.

Sapcut, you are wrong!

Being able to isolate FOC from mass, shaft thickness and differences in friction between varying materials is right out the window.

I still think that FOC is the equivalent to the latest fad diet and it causes bowhunters to make stupid decisions (e.g. sacrificing shaft durability by going to ~8 gpi shafts in order to achieve some arbitrary % of FOC to achieve a benefit that may only exists on the internet).

You don't get the change in direction that you will see in animals in OSB or ballistic gelatain.

Good luck this season guys.

Now I do think a decent amount of FOC is a good thing and I like 9%- 16%. I can tell the OP I was setting up some light 3D arrows with those light nib points and I spent some time trying to figure out why I wasn't getting the same or better groups as my 500gr 13% FOC hunting arrows.

Long story short....the arrow didn't have enough point weight to sit down on the rest at launch. A wrap inside my loop for down pressure solved it but this is unnecessary with a little more FOC.

Once again, a common sense target is irrelevant as long as it is used for all "tests". A piece of OSB will have the same effect on all arrows shot into it. There isn't the varying degree of fiber thickness and glue layers one might think. It's actually more consistent than fur, hide, bone and muscle...

BTW, up your 775 grain arrow in the front with 250 plus grain FOC. total weight still being 775 and check your results. 117 grains up front? seriously? Im surprised it didn't try to go in backwards.

But aren't we missing or have forgotten the point here? Back up a bit. What is the original objective of wanting to know anything about arrow penetration?

Is it because we want to know which arrow will bury the deepest into a Mckenzie target penetration contest? Is the objective to find out what will give us the best indicator of which arrow will penetrate the deepest into the most sheets of plywood? Or is it because we bowhunt animals and want to know the best indicator of how our arrows will penetrate said animals we hunt?

What is the objective of the testing?

If I want to know which arrow build will penetrate an elk scapula, for instance, would I use a phone book or a mass of gelatin or 3 sheets of plywood or would I use an elk's scapula? Out of the above choices, which would be the best thing to use to find out the stated objective?

Am I missing something?

An arrow that goes 12 inches through a sheet of OSB will go deeper into the chest cavity of a 360 class bull elk than an arrow that only goes 8 inches into the same sheet of OSB.

The relative comparisons are the same, no matter what.

If you do the typical YouTube video of a pork shoulder and ballistic gel, what's to say your arrow this time didn't deflect off a plane different than the previous shot? The more consistent and controlled the test target is, the better your "predictable penetration" result will be. Use a common sense approach and you can't go wrong. Try to overthink it, and you'll be off in the weeds before you know it.

I don't see why you are surprised at a 420 grain arrow with 117 grains up front, it's fairly standard for 65#-70# bows. It flat blows through elk. I prefer more head weight personally but still don't need to exceed the 420ish arrow weight for my draw weight.

Shooting materials as a hardi plank or OSB plywoods actually do very well, they show the best penetrating arrow for a particular poundage into a consistent substrate, it does carry out into the field even if it doesn't agree with ones expectations. It helps to give us some intro on what may be the best setup & combination for us.

ElkNut1

It doesn't matter where the weight is. It only matters that the spine is correct for the energy YOUR COMPOUND BOW produces. To increase penetration, these are the areas it can be done :

Increase weight/mass

decrease friction/resistance

increase speed

This is what ElkNut1 has been trying to say/show all along...

The only thing independent of the other two is friction/resistance.

With all things equal except the location of the center of mass of the arrows:

Does an arrow flex more or less upon contact with a highly resistant medium?

Does an arrow flex more or less upon contact with a minimal resistant medium?

Does it reqire energy to flex an arrow?

Is the energy required to flex an arrow somewhat proportional to the degree of flex?

Will the energy required to flex an arrow deminished it's penetration?

Will the location of the arrow's center of mass effect the degree of flex?

That's pretty much it in a nutshell.

Your questions are sorta right. The arrow with high FOC will flex less.

But... That same arrow will flex more when launched from the rear during the shot.

So it is a balance (like most things in life and on the bowsite)

You are getting close to the answer.

Here is my logic:

FOC is greater than zero. So more weight on front half of arrow. So arrow flexes more to get the front half from 0 to 300 ft/sec than it does to take the back half from 300 to 0 ft/sec.

Also, the arrow will be going slower at impact than at launch.

A typical bow gets the arrow up to speed in about 22". What distance does it take to stop? Remember, the force on the arrow causing it to flex is F= ma .

If you hit plywood or a shoulder blade, it could stop in a few inches.

If you don't hit big bones, it could still be going pretty fast as it leaves the animal.

Since we're talking penetration, we really only care about the first scenario. So, I concede that the arrow will flex a lot less on impact than at launch. So I also concede that higher FOC should lead to higher penetration. (but there always a limit, I doubt that a wimpy arrow with 99% FOC would launch very well)

The setup you described above with the 100 gr broadhead and 340 FMJ's is more than adequate for elk.

Go have fun, don't worry about it, and good luck.

There's a lot more to it than F = ma. I'd suggest going and doing something more constructive...

Congratulations. However you should have stopped there.

How much will the arrow flex if it hits heavy bone after it has traveled through hide, muscle, etc, and lost 74% of its speed?

Would a higher FOC help or hurt in that scenario ?

More importantly, how much KE lose due to flex are we talking about?

What shaft are you shooting? Just curious what shaft will give a total arrow weight of 420 grains with 192 up front.

Thanks Toby

I'm a trad archer, both recurve and longbow. I/we DO shoot heavier arrows than most compound guys. My recurve is 52lb, and I hunt with 2117 aluminum at 29-1/2", with either 155 or 175grain Grizzly single bevels...for about 12 grains per pound. About 560ish grains.

That said, dispite my rather heavy choice of broadhead, I'm not all ga ga over foc or efoc. I pay it no mind. I set up...tune if you will...what works on my bows, and away I go.

At times it seems it matters not that the arrow passes through the critter, but how far past said critter the arrow lands. My question is; which arrow kills em more dead ;^)

Saddly...I'm no longer able to chase elk, and am resigned to hunting my local whitetails. They're not that difficult to pass thru, but I still hear the foc arguments echoing about.

And...I still entertain myself perusing said threads...

They don't let me out much.........

Regarding your desire to win a smooth $million...

----> "One arrow is 400 grains, one is 600 grains and you get first pick. Which arrow are you going to choose to get that arrow deeper than your opponent.

"If I want to know which arrow build will penetrate an elk scapula, for instance, would I use a phone book or a mass of gelatin or 3 sheets of plywood or would I use an elk's scapula? Out of the above choices, which would be the best thing to use to find out the stated objective?"

"JRW, have you ever built and shot a tuned 30% FOC arrow?....with a compound bow. ?"

....has anyone here built and shot a tuned 30%+ FOC arrow from a compound bow. Anyone?

Obviously, all things being equal, 600gr penetrates further than the 400gr. What do I win?

Now, answer this question. We go to an unmarked 3D course with ranges out to 50yds. One arrow is 400gr, one arrow is 600gr. Which arrow are you going to choose that is most likely to hit closer to the 12 ring?

Not everyone shoots trad. Not everyone limits themselves to 20-25yds. If that were the case, then yes, I agree shooting a 600gr arrow would have zero downside. However, for those that don't, it does have a downside. That's why MOST people that shoot compounds realize there is a compromise between adequate weight and adequate speed. The overwhelming majority also realize that weight falls closer to 400gr than it does 600gr. Laser rangefinders certainly make life simpler, but most people understand you don't always have the luxury to use said rangefinder.

"....has anyone here built and shot a tuned 30%+ FOC arrow from a compound bow. Anyone?"

I haven't, nor would I have any reason to even contemplate such a contraption. I've killed a couple dozen elk, as well as a moose. I have NEVER considered FOC when building my arrows. I shoot as heavy an arrow as I can, while still maintaining the speed I desire. FOC has always been a by-product, not an objective. I've killed one elk that I got less than desirable penetration, and that was back in the lightweight arrow/overdraw era. Luckily, I still killed the elk, but I learned my lesson. That said, the less than desired result was due to a lack of weight, not a lack of FOC.

To answer your question...not to avoid giving a straight answer but my first thought is I'm not sure which one because if my sights are on then I'm not sure it matters. I guess when using sights and a compound bow the winner is the one who judges the distance better. So I would think the flatter 400 gr. arrow will forgive you more for your yardage estimate errors.

Sapcut, I would not hunt Elephant or any dangerous game with a 60# bow. I'd be at a bare minimum of 80# so the question you ask is a bit off line. As far as which arrow will penetrate better it is the 400ish grain weight because you are only shooting 60#. I would shoot a 415-420 grain arrow that will out penetrate the 600 grain arrow. 60# compound limbs only create so much energy & 600 grains is too much arrow. You would have to get to 75# or so of draw weight to overcome the 420 grain arrow with the 192 grain head weight. I will have photos tomorrow that should help us both out! Thanks!

ElkNut1

I bet "0" have and I would bet that a couple here, if even that, may have built them for trad bows.

The theory that EFOC or even just a few points beyond 10 or 12% will increase penetration efficiency is plausible when you consider the basic physics involved, I have built 30% FOC arrows and shot them from one of my longbows but I have yet to set up a real test/comparison for penetration.

That is not off line regarding my contest question. It has nothing to do with hunting...just burying arrows.

"60# compound limbs only create so much energy & 600 grains is too much arrow.'

For a 60# compound? What? too much arrow. Ok, I respect your opinion but that is extremly difficult for me to believe.

Have you measured the FOC on that VAP 350 with 192 up front?

I can't recall any compound shooter ever discussing using a very high FOC arrow....even though they have super strong opinions on how they don't fly better or penetrate better.

I don't even know if its possible to get the right shaft material with such a powerful shooting machine.

It would be interesting for someone to do that.

As more people understand FOC and come up w/ their own theories to test we will see more and more of those tests. Lets just hope it doesn't involve a side of pork or a rack of ribs.

If a 600 or 700 grain arrow is to be the better penetrator the bows poundage would have to increase to 75# or more.

We are talking compound bows here not trad gear. If trad gear was the concern that changes things because of their very low FPS compared to compounds higher FPS.

Photos to come!

ElkNut1

As I have said for years now, I give no value to shooting anything but real animals and the materials they provide IF I wanted to found out what would give me the best chance of penetrating the same materials. That is why I have no photos. Although this means nothing to me as well but I'll mention that my 671 grainers penetrate my worn out Mckenzie deer taget less than the 856 grainer. But again, that means nothing really. Way to many variables that can't be eliminated.

Elknut.... the arrows in the photos exited the plywood, correct or no? The shaft diameter appears to be much different, correct or no? If either is correct. How do you not comprehend that that would be kind of important to eliminate? I am just kind of playing along but even if you DID eliminate all variables except the one you were concerned with (weight in this case)...the hurdle still stands that your are not shooting the same material your hunting....IMO.

"We are talking compound bows here not trad gear. If trad gear was the concern that changes things because of their very low FPS compared to compounds higher FPS"

If you will, expound on that. Are you saying that a slower 700 gr. arrow from my 71# recurve will do more penetrating damage than the same weight arrow going much faster from a compound?

BTW, how do you explain the penetration differences in the two 420 grain arrows?

A friend went to a lower GPI shaft to get high FOC and a ~420 gr. arrow and broke one and maybe two shafts on game where he had never had an issue with the ~9.5 gpi shafts he had previously shot. The sample size is low, but I believe guys chasing Ashby's #5 or #6 predictor of penetration while forgetting #1 are working towards a predictable outcome.

"A lighter shaft DOES NOT mean a loss in durability. Good materials engineering design can give you good toughness in a shaft and weigh less than conventional traditional manufacturing processes."

Convince me that good materials engineering will allow a lighter shaft using the same manufacturing processes and materials to be as strong. While theoretically speaking you may be correct, practically speaking I think you arguing apples versus unicorns.

A lot of things operate via a bell curve, at the extremes you lose efficiency leaving optimal performance somewhere in between.

Your preaching to the choir regarding structural integrity.

Funny, the last time someone said something like to me I was writing a term paper and he had a PhD...

Easton HEXX and Da'Torch arrows. The 330 spine weighs 7.9 gpi. Lighter shaft but holds up to the classification of a .340" deflection of static spine. No fairy tales here.

In reality, you could go lighter and stronger, but that would be too cost prohibitive to Mr. and Mrs. Consumer.

I confess, a little over a decade ago I sipped the Ashby koolaid. I tried to build one for a water buff hunt and was having a problem 1) getting over 30% foc and 2) my 28%ers were grouping terrible.

Now many of the EFOC guy have shouted me down saying i must have done something wrong.....and they are CORRECT: I put too dang much weight out on the end of my arrow!!!!

Big difference between an 80 longbow vs an 80 Bowtech with speed cam modules.

Instead of 500 gr of point weight i used arrow tubes with i think 16% foc and my arrow was a complete pass thru on a 2,000 water buff....double bevel bh even.

Sweeeett!

The problem was not EFOC on your attempted arrow. It was untuned just like any other untuned arrow. Surely you know you just can't add weight to the front. IF, big IF, you wanted a EFOC arrow.

FWIW, I agree with your assessment. I agree with Wyobullshooter. I agree with Sapcut. I do know first hand the benefits the heads required to obtain EFOC, offer over standard weight broadheads. I also think that doesn't apply unless you are radical in shot selection. I KNOW speed has it's place in the penetration world. I KNOW there are diminishing returns as you are saying. I'm just pointing out is it the increased speed or the increased FOC making that lighter arrow penetrate more?

God Bless men

Never use a target material that allows the tip the arrow to exit the material. Once the tip even starts to breaks through, the resistance is reduced exponentially. Therefore even a slight difference in the their true penetration potential is highly exaggerated.

Shoot 3-5 times to see if you get consistent results. Even shooting the exact same arrow into the exact same medium will yield a range in penetration. Foam will often show a range of 1" for the same arrow.

The target material must be absolutely ridged. If the target material moves, it's the same as shooting an untuned bow. Target materials that are allowed to move or flex can yield a variety of results depending upon where the arrows hit.

Only change one variable. Keep everything else equal. You can't shoot arrows of different diameter and different weight and claim the results are only due to one of the variables. Enknut1’s test on May 12 does not prove anything and is worthless on many levels. His belief may be correct, but the test does not demonstrate it.

It consists of waste wood chips and glue. Throughout a sheet of OSB there are many differences in the ply.

One shot could hit a couple big wood chips and another hit a bunch of sawdust and glue

There is a fellow on Leatherwall that came up with a "Broadhead Penetration Contest" (Rick Barbee)and the medium was a type of foam board glued up. It should be about as consistent a medium as one could come up with and should work well if kept rigid.

I am only guessing here but so are most of you but my opinion is that you wouldn't see a hell of a lot of difference in penetration between 10% - 20% FOC and getting higher than that from a 70# compound may prove difficult and/or the arrow may end up being a lot heavier than the lower FOC arrows creating an unwanted variable.

Ashby spent a hell of a lot of time shooting and comparing, probably more than the entire population of Bowsite and Leatherwall combined. He would have seen enough of a trend to determine what he said.

They can get the spine, but can they get the durability? The two are not equivalent.

Sapcut, I agree not much can be had or cemented with a solid conclusion by shooting worn 3d targets. This is why I have used quite a few different substrates over the years with the end conclusion all being the same. At no time has a too heavy arrow come out the victor for a particular bow poundage.

I too am concerned with penetration on elk sized animals, this is what I test for. Not sure how many have to be killed but my son & I have our share & then some. The weights we hunt with these days blow through elk with ease at 66# & 70# -- In the past we were getting aprox 15%-20% pass-throughs with setups in the 480 grain to 565 grain arrows, since the penetration tests we found our arrows were too heavy for our poundage & started testing for better penetration, since then we receive 100% penetration other than on 1 frontal shot where the arrow buried completely in the elk but did not pass through the full length of the elk.

As mentioned earlier shaft diameter does not come into play resistance wise as much as many think it should, guys try it yourselves & you'll see it's minimal at best not inches in penetration difference that some believe. The testing today should help with some of the thoughts by many here.

I am shooting the exact arrow & head weight in these tests as I hunt with, there's no tricks here just simple testing to see what penetrates best, period.

A 700 grain arrow shot out of a 70# recurve is lucky to be at 175 FPS. A 700 grain arrow out of a 70# compound would blow away the penetration value from the recurve. This is common sense. The question here is, is there a better suited arrow out of the compound at 70# that would best the 700 grain arrow with more speed, flatter shooting & better penetration, yes there is.

Simple, the 420 grain arrow with the much heavier head weight penetrates better than the lighter headed arrow even though both are the same weight. No mystery there! (grin) The issue that arises is guys get too carried away with TOO much head weight & defeat their original purpose. In order to shoot 250 grain head weights you must jump up in spine & overall arrow weight increases to a too heavy total arrow weight for a given draw weight.

cnelk, I've used lots of materials over the years from actual Plywoods to OSB to hardi plank sidings & more, at no time has an arrow that is too heavy for a particular draw weight won, not in one single instance. To say certain things are inferior simply is not true. We shoot multiple rounds when we do this so we have a good balance of what penetrates best. If there were soft spots in the materials don't you think the heavier arrows would win at least once out of hundreds of rounds! (grin)

ElkNut1

Someone disagrees with 'The' elknut and mini novels are written and threads resurrected with only his opinion

BTW - Wyobullshooter & Sapcut said it best...

That said, even though I do shoot strictly stick bows, I don't get carried away with foc.

As I mentioned earlier, I'm primarily a whitetail hunter, and really...just how much does it take to pass through a deer?

The one thing Ashby's studies did sell me on is the two blade single bevel broadhead...especially for my sticks. I now shoot only Grizzlies...175 grain for recurve, and 155 for longbow.

The "s" cut is real and devastating...as is the bone splitting capability.

I shot compounds back from the late 70's through the late 80's, and used mainly 4 blade Rocky Mountain Razors...a blast from the past there, eh? Lol. They performed great for my application then with bow weights from 70 to 89lb, on 2219's.

My WhippenStick Phoenix was chrono'd at 196fps at 9 grains per pound...I hunt at about 12, so it's a bit slower but hits hard. It's 52lb at my draw.

As WyoBullhunter referenced earlier, today's 3-D shooters go lighter for flat cast competition shooting. Subsequently, for my 53lb longbow, I drop from 12 to 9 gr per pound with 100 grain field tips...for 3-D. Huge advantage. I'll hunt with the heavier arrows with the 155 Grizzly. At 20 yards both arrows shoot pretty much identically...it's beyond that where the drop off occurs.

Seeing as my hunting spots are too thick to shoot longer, it's not of importance.

We are all anxious to see the results of a good test.

So the rest of the story on my attempted EFOC arrow; I did my normal tuning procedure with BH tuning- perfect. Where I was having problems was in group size. The one advantage in shooting for years is you know when your groups at different ranges open up....and mine were badly with the EFOC arrows.

I was really getting some flyers especially when kneeling and shooting 3D in hunting type situations. The only thing I could figure was a minor form flaw [like in real hunting conditions] and I was getting some bad flyers....which I wasn't getting with a more balanced arrow.

Speculating here but I think the 80# allegiance with speed mods [getting over 100 ftlns of KE from that beast] just made the EFOC arrow more critical to shoot....I just don't get arrows that are 6" out of my normal group at 50 yds.

Have you tried shooting an EFOC arrow from a Fast compound?

I have no doubt a guy can tinker and adjust and tweak etc,etc and get one of these arrows to shoot. And I can imagine a scenario where a longbow/recurve gets a better result from an EFOC arrow as those bows shoot fine with lighter spine arrows. If a guy wants to do all that I say more power to him- different strokes.

I can tell you in my case I dinked with it for a couple weeks......when in almost all cases I can work up a bow and arrow with higher spine combo in a compound that shoots lights out in a couple hours. In fact, in my own testing I have come to appreciate that shooting a higher spined arrow just works better in a compound. I was getting better speed in my chrono from the heavier spined arrow of the same weight....3 fps on an 825 gr arrow as I recall. I think a lot of problems guys see with BH arrow flight is due to being underspined.

Bottom line though, IMO, its not worth the many sacrifices of the EFOC arrow. We know there is no accuracy advantage or more guys that rely on accuracy would use them. The claimed penetration advantage is a lot of hocus pocus. Heavy = better penetration. If EFOC is an advantage its never been difinitively proven and if so...its statistically insignificant. I will take the stiffer arrow for its many advantages everytime

"I will take the stiffer arrow for its many advantages everytime"

Isn't the stiffer arrow the EFOC one? I know to get myself to 30% FOC I had to go to a stiffer shaft to tune it and its the greater stiffness that promotes more efficient use of the arrows energy at impact. No?

Adding 50gr inserts and shooting a 100gr BH VS shooting 150gr BH.....FOC can be different even tho weights are equal. BH design has a lot to do with it.

Bottom line is....even if your tests indicated anything substantial, you must control all variables except your one constant.

I'm of the opinion that EFOC is taking credit amongst the believers for something that is caused by another...such as a stiffer arrow shaft. This based on many many years of shooting animals, Elk, Moose, etc.etc. with basically a slightly more weight forward than balanced arrow but with a very stiff shaft, zips through most animals like it never hit them.

That is the info. that I have often wondered...whether a EFFOC arrow would even work with such a powerful and fast compound. Apparently not. I guess just about everything is more prone to problems the faster it goes.

Not that any compounder had any desire to do so but being the tinkerer I am....I bet a bit heavier arrow with the use of about a 4 inch footing would possibly decrease the flyers.

Good information.

Yep, about as good as anything else. I've broken FMJ's and Axis arrows in similar fashion to HEXX arrows.

What material property you chasing by saying "durability"?

Actually, a pork shoulder roast is. Talk about variations in plane intersection angularity!!

"Never use a target material that allows the tip the arrow to exit the material. Once the tip even starts to breaks through, the resistance is reduced exponentially. Therefore even a slight difference in the their true penetration potential is highly exaggerated."

The best thing is to shoot through 4 sheets of 2" foam insulation (like what you can get at Home Depot) stacked back to back then have a piece of 1/4" dry white pine behind that (no sawdust or wood chips). After the foam has done its slowing-downness on the the arrow, the arrow with the most zing to it will stick out of the pine board the most. On second thought, maybe just use 24" of 2" foam insulation instead, that way only the pinchilivity ability of the foam on the tip of the field point and sides of the arrow will slow it down and the arrow with the most zing to it will go the deepest. Make sure to measure with a calibrated caliper, not a Stanley tape measure.

p.s. sapcut, the animals were brought up by you, I responded to it. Here's your quote sir! Thanks!

"As I have said for years now, I give no value to shooting anything but real animals and the materials they provide IF I wanted to found out what would give me the best chance of penetrating the same materials."

ElkNut1

Not to be snarky, but do you have any data to back that up? The reason I ask is a friend went the route of using a lower GPI shaft with the same spine/manufacturer as the arrow he formerly used to chase higher FOC, but he experienced poorer durability with the lower GPI shafts. It stands to reason that achieving the lighter GPI needs to be done by using less material, and while an arrow may have the same spine or stiffness to resist forces from a particular direction, it may not be as strong when tested in other planes.

Foam is an interesting test medium (and perhaps the best commonly available medium), but I have noted that different shaft types can provide varying levels of friction which can influence penetration independent of the actual energy carried by the arrow. Given flesh doesn't stop arrows as much by friction along the length of the shaft, I remain a bit skeptical of results of foam tests.

Data? Really...? An arrow hits a solid tree or rock, it's gonna break regardless of what or how it's made. A broke shaft is a broke shaft.

The point is, you can get a lower weight shaft and keep stiffness or rigidity. If your arrow hits the intended target, assuming proper selection, the toughness property of the shaft will hold up.

I want to thank a few of you for staying on track & sharing some great info with myself & others. GotBowAz, Sapcut, Matt, Beendare, HDE, Purdue. You all play a huge part in really understanding what drives arrows! I've done lots of tests over the years & feel good about them in suggesting a variety of arrow weights to others so to be well equipped for ones hunts.

BUT! For those who feel that there is little gain with FOC or heavier insert/head weight you need to either do testing of your own or rethink it & listen to ones who have went through the trouble with experimenting, it's not easy! I've known for years that having a heavier insert head weight created more penetration but my eyes were opened even wider by GotBowAz & Sapcut especially! Thanks guys!

Matt, you are spot on with making sure your target of penetration has to be solid as a rock with no twisting or movement on arrow contact, this can be as much as 4"-5" difference in penetration if not monitored. Thanks!

Beendare, I agree spine is the biggest cause where hunters or testers are failing in their efforts when reporting arrow failures. Wait till you see one photo where your words ring true sir, thank you.

Guys, it doesn't matter what medium you use when testing penetration value, just keep things consistent & you will see there are arrow weights that just do better no matter what! There will always be those ones that disagree but as long as you see great results from your tests stay with it & ignore the naysayers!

Photos & explanations coming.

ElkNut1

I would imagine it would be similar to metallurgy, to make something stiffer using less weight it usually has to be made harder. Which means while it would resist flexing more it would be less forgiving when flexed or impacted to the same degree. i.e the "harder" material would fail sooner when both flexed to the same degree.

I know that weaving patterns, layup, etc. can be manipulated some to achieve that, but for the most part to make anything both stiffer and lighter you will sacrifice "durability" to some extent. It will be more "brittle".

To go though what it takes to make a high performance compound shoot EFOC.... why? A mid weight arrow with 10-12% FOC will blow through any game in NA. And you don't give up a bunch of shooting range to do so, a real sweet compromise. Stacking arrows, grouping well, hitting with the FP out to 60.... Tell me why I need EFOC again? Why I need to shoot a 600 grain rainbow?

There may be something to it for trad shooters, they have to tune their bow by arrow flex. And equipment using less energy and shooting slower gives a bit more forgiveness in how they shoot. But for most compounds you're giving up more than you can gain.

Start off with what issue you may want to improve and go from there, not the other way around. If you want penetration, nothing is going to work better right out of the gate than simply screwing on a broadhead designed to penetrate.... like a good coc two blade with a nice long blade angle. (and ironically, that fits the description of the majority of heavy heads used to get EFOC as well... who'd a thought....)

No, not really...

I respect your personal preferences but...really? Is the trajectory really that undesirable? The video posted suggest maybe it's not too terrible.

But 600 grains from a compound would be filthy violent!....and probably should be banned.

I know too well what 830 grains up to 994 grains will do to deer shoulder bones and large boar armour.....and that's floating in there at about 170 and 150 fps. from a grease gun.

Can't you imagine yourself what just 600-700 gr. would do at 250+ fps. There would be no bones in the body, any body, that would stop it. That would not even be fair chase any more.

My bad.

650 grainer at 220 fps ??

In '92 and '93 I was wildlife biologist and bowhunting guide at Tara and Willow Point Island. Hundreds of people from all over the world came into that place to literally puncture deer. Seems like every one of them shot the absolute lightest, shortest arrow with overdraws and lightest broadhead, like 85 grains, while staying legal. I believe the High Country Safari was the deal at that time. I was thinking they were pushing 300 fps. Maybe not.

Without fail, we trailed deer every day and night with labs. Inches of penetration was atrocious. Embarassing atrocious.

The guides played a different game, however. They shot the same kind of Safari bows but used full length swaged arrows with 150 grain snuffers. No idea what that bullet weighed, (500-600 gr. perhaps), but they destroyed lots of deer bodies. That sold me quick on what the lack of weight means to penetration.

When easton started trying to make very light aluminum shafts that had enough spine to handle heavier and ever faster bows.... Harder aluminum, thinner wall/larger diameter.... I shot 2514 years ago, I think they had 2512 and such... but WRT bending or banging them they were pretty delicate in comparison to the heavier shafts.

Always a compromise. Technology does tend to narrow the scope of those compromises, but still compromises....

Doesn't that depend on what materials you are comparing? Some lightweight materials are much stronger that heavier ones. What does durability have to with FOC anyway?

BTW, The hardness of of a given metal has nearly no affect on its stiffness. That is a common misconception.

For instance; a piece of tie wire (bailing wire) will break at a certain amount of tension. Carbon fiber strands will break at a much higher load of tension. Take the wire and tie a granny knot in it and it will still break at a certain tension load but less than it's original. Do the same thing with the carbon and it will break at a much lower tension load, in fact, you could probably do it with your bare hands. Reason? The carbon has nearly zero shear strength ability whereas the wire, because of it's ductility, will stretch to allow the higher load to break it. Arrows under go tension and compression while in flight and at impact. Weaving patterns helps to distribute the sideloading forces as a component of compression.

In metallurgy, you can do some really cool stuff with alloying to get high strength-low weight use. You don't have to only achieve hardness through quenching and grain refinement.

Yes really. I am not talking rocks or trees, and am talking animals. How much weaker is a 7.9 gpi shaft than a 9.5 gpi shaft (20% difference in mass) that uses the same materials and manufacturing techniques? It would be sophomoric to say there is no difference in durability because the spine is the same.

The anecdotal experience of my a friend who didn't break shafts on game until he went down the rat hole of chasing high FOC and switching to a light gpi shaft to achieve it suggests the answer is somewhere between "just enough" and "a lot".

It does, and let's just assume for the sake of this discussion we are talking about the same materials - like the ones used in carbon arrow manufacturing.

This week I tested the VAP arrows .166 diameter(7.8 per inch) with dozens of shots through 2 layers of 3/4 plywood with zero issues when the proper spines were used. A lot of it is proper spine, this is why I prefer shooting one spine higher that recommended for my setups. Charts show I can easily use 400 spine but I prefer 340's & at times 300 spine at 66# & a 27-1/2" draw length. It depends on my head weight for my decision.

After some testing this week I'm a firm believer in more insert/head weight, these two can make a dramatic difference over arrows of the same weight with less head weight in penetration value. Of course there's extremes but stay balanced & you can build a monster in the 400 to 475 total arrow weight depending on your poundage drawn. Trick is to have a minimum 175+ grain insert/head weight if interested in serious penetration, it's not needed in most cases but some just like the idea! (grin)

ElkNut1

Shooting an animal and saying those results mean best "durability" is what is sophomoric...

Just because an arrow has more wall thickness DOES NOT mean it has better strength or performance properties.

Let's not go any further on this, as pointed out, this has nothing to do with FOC.

Again, any test data to validate that contention? All else equal, I think even arrow manufacturers would disagree with that. That isn't to say that a high end light gpi arrow from one manufacturer might not be more durable than a low end but higher gpi shaft from another, but with arrows within a given quality range across any given manufacture's product offering I highly doubt they would agree.

This is a very relevant topic in the discussion of FOC because I have read about a number of guys who have gone to light gpi arrows to try and improve FOC, and I personally believe they are making short-sighted decisions to chase FOC at the expense of arrow durability,as I do not think these lighter gpi hold up as well to glancing blows and changes in direction that we can see when shooting animals (but not so much when shooting plumb into plywood). I don't raise this as some theoretical objection that many are fond of adding to these discussions, but based on anecdotal experience from a friend who went down that path and had bad experiences on animals.

This reminds me very much of the discussions in the 90's where guys were decrying poor performacnce from mechanical broadheads when they had never made an effort to tune their bows. They were unwittingly compounding factors that reduce penetration, and the increased risk of failure could be predicted before they even went into the field. But it was the broadhead's fault....

Matt, I understand your point to HDE but I would suggest if an arrow is tuned or not, a mechanical broadhead will decrease your penetration potential compared to others. Of course, as usual, I am not nor ever referring to a soft tissue rib cage perfect shot.

But there are several aspects of the topic that are being confused IMO. One is the difference between FOC and just plain cumulative arrow weight. If the energy from the bow was delivered to the arrow at 100% efficiently and was imparted to the target the same, then there would be absolutely no difference to penetration between arrows of differing FOC. Weight X speed would remain constant.

But this is where it gets muddy. If you shoot a very stiff arrow with a moderate weight point, from your compound, the shaft will flex less and absorb more energy. When a shaft straightens out it does so in both directions, fore and aft. Any energy stored in the shaft and then lost to the aft is gone. The exact same thing happens on impact deceleration. The shaft "noodles" in a series of s waves. And now it once again will lose energy as it straightens with the lose to the aft gone.

A trad bow will impart it's energy over a longer more even curve. Less " violent" if you want. The lighter shaft used to facilitate the heavier head will not be subject to an extreme compression because of the slower loading of that energy. BUT, inflight, the shaft will straighten more to the aft because of the resistance of the heavy head. Gain some loose some. The same happens at impact deceleration, but since the head has stored much of the energy {weight X speed] the lose from shaft oscillation will be less. Think of a spring with a weight on one end. If you released the compress spring evenly the weighted end would travel less from the center than the weight free end. The heavier the weight to spring ratio, the more exaggerated the results.

A heavy head and light shaft may suffer more angular deflection when changing direction on glancing impacts, like the side of a leg bone. A lighter object, the shaft in this case, is more easily deflected from it's course than a heavy one. The heavy head will be less deflected, but the nock end of the shaft more, so shaft angle is no longer being applied directly to the entrance. Same result as a poorly tuned arrow flying out of plane.

For some of you guys familiar with air tools, you know that when using an air impact gun to remove very tight bolts, you get the most efficiency when having the socket directly on the air gun. The longer the extension, the more energy lost at the work point. Your tool is producing the same amount of energy, but you are loosing it due to transfer lose. And before you ask, I use impacts everyday. Your, bow, arrow, broadhead combination suffers from the same physics.

Sapcut may well have the optimum setup for the way his bow stores and transfers energy.

And using a stiff shaft and moderate point weight with a middle-of-the-road total arrow weight is probably ideal for a modern compound.

Last week. three us us went bear hunting. We killed six black bears, three of which were big. All six were shot with 1 1/2" Spitfire expandables.

My setup; #60, 29"DL, 125 gr head, 400 spine, 450 gr total arrow weight. Two complete pass throughs. I should say that I have a 7/8" footing on the front of my Axis and a 3/8" collar on the nock end. Makes the Axis almost indestructible!!

Ist Buddy. #70, 29 1/2" DL, 100 gr head, 340 spine, 450 total arrow weight. Two complete pass throughs.

2nd Buddy. #60, 26 1/2" DL, 100 gr head. He was using a 200 PSE X-weave cut to 28 1/2" so not sure of the exact spine or total weight, but it felt light. Both arrows stopped on the far side but killed very quickly. [edit, looks like 437" spine and 7.5 gpi.]

Wow, long post, sorry. My typing finger is tired.

What doesn't have anything to do with FOC is whether a lighter shaft is stronger than a heavier.

Matt, a HEXX arrow has a wall thickness of 0.030" and an OD of 0.283". An Axis arrow has a wall thickness of 0.035" and an OD of 0.264". That is only 0.005" difference but a delta OD of 0.02" on the lighter shaft side. What holds up better all around for rigidity and bending, the skinny one or the bigger one? Years of drillstring design and buckling issues tells me which one...

Build me a 6-7 gpi shaft that spines at 300, actually with a heavy head it will have to be 300+. Now build it just as tough as a 9-10 gpi.... I might consider trying to build a EFOC arrow and try it. Right now I know of no such animal. Could be they are out there and I'm just not aware. That a commercial shaft that meets that criteria exists.... that is what concerns me. Not that it "can" be built. Most anything "can" be built. But it is an issue to build anything that is lighter and meets all previous criteria for strength and toughness, to improve on what is already pretty much state of the art. No compromises.

Again.... back to head design, ever notice those heavy EFOC heads are pretty much designed for penetration, long blade angle two blades? Not many 175 grain expandable or even short 3 blades.... And wow... people are impressed with their penetration... EFOC given credit once more..... huh... whoda thought....

But the same head design... on a conventional FOC arrow of equal total weight will not have equal performance?

Not according to the extremely thorough Ashby reports compilation ......when heavy bone is hit. Not soft tissue hits but heavy bone hits.

Can you explain exactly how your buddy's arrow was broken by an animal?

"How much weaker is a 7.9 gpi shaft than a 9.5 gpi shaft (20% difference in mass) that uses the same materials and manufacturing techniques? It would be sophomoric to say there is no difference in durability because the spine is the same."

Matt, I'm not sure that the scenario you want is possible. If everything is equal (material, mfg. tech., OD, and I assume less wall thickness for the 7.9 gpi). How can the spine be the same?

Something to remember when comparing the potential for breakage between a light and heavy arrow; the light arrow may well have 10% less energy trying to break it. Bow inefficiency and frontal drag will lessen its velocity (KE) at the target compared to the heavier arrow.

Ambush, "A trad bow will impart it's energy over a longer more even curve."

The power stroke of each are about the same. In fact the trad bow may be a bit shorter. The draw curve is shorter too. However, you are correct, the acceleration is far less with most trad bows.

" The same happens at impact deceleration, but since the head has stored much of the energy {weight X speed] the lose from shaft oscillation will be less."

I'll have to disagree here. As I said much earlier in this thread, "it just depends". In what distance is the arrow stopping? How fast was it going when it hit? It accelerated over about 22" when it was fired. If it stops in 3" the deceleration could be more violent by far than the acceleration.

Each case is different. It depends upon the bow, the arrow, the range, the FOC, the target, etc.

Someone asked about my stiff spine comment, I like a heavy spine med FOC arrow- they hold up well and hit hard with little flex ....I think for the reasons Ambush mentioned in his post above.

Overdraws; I would concur with your observations Sap. I shot 2213's in an 80# compound for a few years back in late 80's- fast and light-and couldn't figure out why my arrows weren't getting good penetration.

It's easy to sit at your PC & say it's a poor medium, try it yourselves & you'll think otherwise very quickly!

Here's two arrows through both sheets, one has a total of 117 grains of insert & field tip weight & the other has a total of 192 grains insert & field tip weight. Both arrows weigh the same but the higher FOC is the clear winner in penetration. These arrows are properly spined at 340 spine 66# compound 27-1/2" draw.

ElkNut1

So are you saying total arrow weights with every thing included is

117 grains tip and insert + 420 grain arrow = 537 grains total?

192 grains tip and insert + 420 grain arrow = 612 grains total?

or total weight with both FOC set ups are 420 grains?

If it is the later how did you get both arrows with the same GPI exactly the same 420grain weights? or are the arrows weight different GPI, or tubes or weed wacker line inside 117 grain shaft? That's what I did to compare them equally.

Good test regardless.

thanks for sharing.

Both those arrows kill elk with no issues. Some guys just like more of a hammer type pounding,like myself! (grin) You can muster up lots of FOC without having to have a lot heavier of total arrow weight. You can shoot up to 250 grains of head weight & still be under 500 grains of total arrow weight & still be spined correctly.

ElkNut1

By the way you really taught me something on the 590 grain test you put me through, you were spot on in your testing! (grin) I have some interesting info to share further on that, that may interest you! (grin) Thanks for your enlightening help!

ElkNut1

With your draw length and a 340 spine you have a lot of options.

Shaft diameter will make a difference, the closer the better. After the shaft enters the board the larger diameter [more surface area] will create more friction and resistance compared to the thinner shaft.

Are you trying to get my head spinning! (grin)

ElkNut1

To test true FOC and only FOC you need the same arrows. In my case FMJ 300's at the same length , one with a tube, cord, or weed wacker line in it and glued into place and the other with the front end weighted FOC. Then you will be exactly the same finished weight total between both arrows, same diameter and same length. only the FOC will be different.

There will be one variable you cant remove though. That will be spine loss with the higher FOC arrow. However if they both tune well it's really a non issue.

ElkNut1

Trophy8, you are right on sir! (grin) I did do that this time with the same shaft, the higher FOC arrow is hard to beat, period! (grin) I tested the same .166 shafts to 243 grain total head weight, the results may surprise some! (grin)

ElkNut1

Since you referenced shooting elk and penetration, put those trusty QAD broadheads on those arrows and then shoot them thru the OSB.

It not legal to shoot elk with field points so the test isnt valid for hunting conditions

The physical potential energy (momentum, Kenetics, etc,) once in flight cannot be altered. Only loss on impact can be mitigated. A stiffer spine has less lost energy.

I've done this demonstration at my work. Take a large diameter ball bearing (say 1"") and stick it on the end of a long light spring. Drop it straight down onto a soft materiel. I use plumbers putty.

Now take the same ball and stick it onto the end of a much stiffer spring of the same weight and drop that from the same height. With weights and height of drop being equal the stiffer spring combo with sink farther into the medium. In this case FOC within hinder penetration.

Another quick experiment anyone can do to demonstrate the angular shaft deflection I mentioned is this.

Go to the work bench and grab your hammer. Ball peen or light sledge works best

Hold the end of the handle between two fingers about waist height and drop it. Take note of how quickly the handle slams sideways Now do the exact thing only hold the hammer by the head. An even release is key, or "tuned" , if you will. Any difference in "nock" end deflection?

ElkNut1

Paul, what is the weight of both arrows without FT's?

That's not true. The only thing stopping those shafts is the friction created by the OSB board. The larger the surface area, the greater the friction(per inch of penetration).

I'm curious what the results are from all the shots with those two arrows, not just the one pictured. To make that test quantified you'd have to shoot each arrow multiple times and record the results. Then you'd have to figure the difference in diameters and therefore calculate a formula on how much penetration to subtract from the smaller diameter shaft.

In the examples above I would trust ElkNut enough to use the correct size FP for the shafts he is using but Xman is right. The larger the shaft diameter the more friction there would be.

You will get a chuckle out of the Ashby presentation to P&Y where he claims the noodlier arrow is better for penetration.

I've seen the effects of a stiffer arrow on game, very effective....all anecdotal I know but its just common sense that the stiffer arrow is going to lose less energy due to flexing, vibration, etc.

Not sure

Could you please post a link to that presentation?

If you follow this stuff long enough you'll find a lot to chuckle about. :)

Whenever the arrow tip passes through or even starts to pas through the target medium the results are misleading. The actual difference in the available energe between the two arrows is the force needed to push the lagging arrow 7" through the hole it created in the plywood. If a 3 pound force is required, then there is only about a 1.6 foot-pound difference between the arrows.

Had he shot into a medium where the arrows didn't exit, the difference in penetration would be very little. Still better for the higher FOC arrow, but not as dramatic.

BTW, friction has nothing to do with area. It is only a function of the coefficient of friction between the materials and the force perpendicular to the materials.

With a 500ish gr. arrow moving at around 200 fps from a 73# recurve, I hit a doe in the scapula, probably the ridge. The arrow went in only a few inches.

Years later I built a 994 gainer, I think maybe 20% FOC, nothing fancy. With that arrow moving at maybe 150 fps for 21 steps, I hit an older buck in the onside ribcage thence destroying the offside shoulder bones and ball joint.

Then another test I remember. I shot a boar thru the face to the vitals with basically the same arrow.

Another test was hitting a major boar broadside thru literally over 4 inches of shield armour, onside scapula and out behind scapula. 830 grains and 32% FOC. I may be wrong but I think a 420 gr. arrow would struggle to do that.

The physics guys are going to have a field day with this!

Warning, this is about the slowest presentation ever....you have to skim it.

And...if its not painful enough.... its broken into 4 sections- this one gives you the crux of Ashby's reasoning [or maybe not!]

Yes F/T are the same diameter.

GotBowAz, your test were accurate, I received the same penetration through the plywoods, the 600 grain arrow with 243 grain insert/field tip was 3-1/2 deeper on several shots over the 420 grain VAP with 192 grain insert/field tip. I couldn't believe it but it is what it is! But I didn't stop there! You'll see!(grin)

Sapcut, don't get hung up on the 420 grain arrow, it was just a measuring stick to go by as a comparison not an end all. That arrow has a FOC of 16.6 -- I then went to 23.2 FOC with the VAP, wow what a surprise that was! It's a thumper! (grin)

Purdue, all you have to do is change the FOC on the 655 grain arrow & it will blow past the 980 grain arrow. Nice thing is it will do it by being over 300 grains lighter! No kidding!

Guys, this testing has been a blast short of blowing a few 300 spine arrows up & one 340 VAP! (grin) That plywood is tough on things! (grin) I also blew up a 340 FMJ. As I mentioned on another post if you're not tuned both bow & spine wise the 2 sheets of 3/4" will reject your offerings! (grin) -- I realize you do not need such over kill to hunt elk but there's no denying what a heavier FOC can do especially when matched up to the proper arrow. No need for 600+ grain arrows when done right! This testing is the heaviest FOC testing I'd done & it helped me see better through some of your eyes, thank you!

I enjoyed the testing but I will stay with my 420 grain VAP with 192 grains up front, this setup is fast & a serious penetrator although not the most penetration I could get out of my setup!

ElkNut1

In sapcut's case, he is talking about and building for specifically hitting big bones and rapid deceleration. So the plywood tests are more relevant. But you should stack enough plywood to prevent full pass through. Better is to cut rounds of dry pine or cedar and shoot them lengthwise. When your done, lay them on their side and split them with a sledge and wedge or axe and hammer. You now have your arrows and heads back looking like they did when they stopped AND some split firewood. Tell the wife you're doing chores.

In elknut's case [I think anyway?] he is talking about passing through animals. When an arrow passes through an animal the rate of deceleration is much, much slower, so less "noodling" and less energy loss from the shaft. The combined weight of a stiff shaft and moderate head will have similar performance to the EFOC setup of the same overall weight. And less nock-end deflection from true course on a glancing hit.

ElkNut1

For your own fun, if possible, make the smaller diameter arrow the same FOC as the larger. The results may surprise you.

Not messing with you, you have chosen an arrow combo that will take care of business.

The VAP is 7.8 grains per inch & the Axis is 9.5 grains per inch. The Axis 5mm & VAP is .166 they're not to far from each other, both are skinny shafts. Thanks!

ElkNut1

The VAP 7.8 gpi has a spine of .350

The Axis 5mm 9.5 gpi has a spine of .340

"There is a shaft diameter difference, but as I've mentioned before it has little difference in penetration as both shafts are gripped equally by the substrate." "Yes F/T are the same diameter."

I believe the Axis is .267" OD and the VAP is .166" OD, but the field point on both is .281" (9/32") OD, how can the shafts be gripped equally? If the field points could punch a clean hole, the Axis would have .007" clearance all around, the VAP would have .058 clearance all around.

Of course the the points do not punch a clean hole. Splinters and wood fragments rub against the shafts. If my numbers are correct, it looks to me like the skinnier arrow has an advantage and this accounts for much of the difference in penetration. You can't have two variables and claim the results are only due to one of them.

For most of us, we already have the tool, bow in this case. We just have to maximize its potential. If you are not maximizing your bow's stored energy or are trying to push past it's limits, then you are short changing yourself.

You need a chrony and a few different over spined arrows and a selection of heads and/or weighted inserts. Plus a calculator or chart for kinetic energy. You don't have to worry about tune since you are only trying to find the maximum weight that your bow will push before your start seeing a diminishing return.

It would be simpler if all compounds stored and released energy with the same force curve, but they don't.

Just start shooting groups of three arrows through your chrony at about twenty yards and record the speed for each group. Add ten grains for each subsequent group.

Your shafts must be over spined for whatever head weight you are using since we don't want energy loss from shaft oscillation.

Take all your groups and calculate the kinetic energy for each. You should see an upward curve and then it should start to flatten. Eventually it will start to drop again.

Somewhere in that flat area will be the maximum weight that will absorb all your bow's energy. The beginning of the flat area should be a good compromise on trajectory and hitting power and near the end will be close to maximum useful momentum.

Or you could do like most of us and pick a shaft, head, weight, spine combo that has worked for you and just keep on killing stuff with it.

It has become abundantly clear there are a number of posters who have an understand of all the theoretical aspects of this discussion, but don't understand the products available in the market, the manufacturing techniques used to produce them, and the notion that inserts are wider than the shaft on which they are installed.

I did use the same VAP shafts to test against one another so maybe it will help out there. Thing is it seems everyone wants to see something different? (grin) I'll share some info here on some results with them. Thank you!

GotBowAz, this is for you, try this one out I think you'll like it! (grin) In the photo below you will see your 600 grain shaft with an insert/field tip weight of 243 grains which is part of the 600 grains. Notice when shot with the 420 grain arrow with 192 grains that the 600 grain arrow won by 3-1/2" -- I shot them a couple of times & 600 was best as you had predicted earlier, very nice sir! Both arrows are the VAP, the 600 grain one is a 300 spine & the 420 one is a 350 spine.

After done shooting them I got to thinking that if I increased my FOC on the 420 grain arrow to the same 243 grains & that would increase my total arrow weight to 465 grains that it would have still have more speed & punch & this should show in added penetration. So I added the exact head weight as the 600 grainer. The results were sweet! (grin) The 600 grain arrow in the photo penetrated 16". The now 465 grain arrow with the added weight to 243 grain tip penetrated to 18-1/2" -- The FOC on the 465 arrow was increased from 16.6 to 23.2 -- This was great! This 465 grain total weight arrow was 135 grains lighter but now out penetrated the 600 grain arrow. The combination of speed & FOC worked great! This arrow is flatter shooting & hits like a ton of bricks!

ElkNut1

ElkNut1

ElkNut1

>>>>>>>>>>>>>>>>>>>>>>>>>

Dang, forgot the photo again! Geez! (grin)

ElkNut1

I think it depends on what you want out of your arrow, total weight with a near center balance point, or less weight (and even perhaps the same arrow weight) with more weight forward.

This thread has heard both arguements of which is better, my thoughts are, it's a toss up and personal decision. But, if you choose the later, make sure the proportionality of weight forward and spine match.

"Years later I built a 994 gainer, I think maybe 20% FOC, nothing fancy. With that arrow moving at maybe 150 fps for 21 steps, I hit an older buck in the onside ribcage thence destroying the offside shoulder bones and ball joint."

A 500 grain arrow going 200 fps you say? Funny, that's exactly what I shoot, and I've put it through everything I hunt up to and including bull moose. Several years ago I too shot a whitetail buck through the rib cage and destroyed the knuckle attaching the off side upper leg bone to the scapula. Blew it apart and stuck the arrow int he dirt. Last year I did the exact same thing to a whitetail doe. Nothing to it.

If you're having penetration problems on deer with a 500-grain arrow going 200 fps, it's not the arrow's fault. ;)

ElkNut1

Elknut; the more you test with that method the more confusing it's going to get. You're trying to implicate FOC into all your conclusion when many of the variances in result are caused by other variables.

With your abrupt deceleration method, a 300 spine will penetrate better than a 340 spine simply because it's stiffness will have less loss due to shaft oscillation which sheds energy. You just "proved" that. But the problem is a 300 spine will not tune to all archers needs.

Take a couple of your wrecked arrows, one of 400 spine and one of 250. Cut them to the same length [at least 24"] and screw one of those flat field points into both ends. Start a couple of two inch finishing nails into a 2X4. Now drive both of those nails in, using the shafts, with a hammer using equal blows. Or just compare a raw spaghetti noodle and a drinking straw.

Also you cannot accurately measure penetration if the arrow tip has exited the stopping medium. You should put several layers of Donnacona board behind your plywood.

In the end a good combination of kinetic energy, momentum and trajectory will best serve most hunters. And that happy medium is being used everyday by many thousands of archers with great results. It's not a secret and it doesn't have to be [re]discovered.

If hunters obsessed less and shot more, many of the problems we try to solve wouldn't be a problem to start with.

Now I have to go out and shoot some of my mediocre arrows. I still have a grizzly tag and hopefully will get a chance to see if they perform as well on a G-bear as they did on two large B-bears last week.

I my world tests are more controlled and bad test give erroneous results. You may be right, that the arrow with the higher FOC penetrates deeper, but your tests prove nothing to me for the reasons above. Glad they work for you. (Grin)

I may do a simple test where I use the exact same arrow and only change the FOC by relocating an internal weight. I was hoping you would show that.

I'm sure any of your arrows will do the job. Good luck with your tests. Time for me to go fishing.

ElkNut1

It will for most if they shoot a modern compound with a release.

I have area youth shooting .300 shafts for the added weight they need for penetration. A 27" arrow with a 125 grain Stinger tunes perfectly out of a youth bow set at 23" and 35#. It's dang slow, but it'll blow through the ribs of a whitetail with ease and stick in the dirt on the other side. All while hitting same POI as their field points.

I had a near pass through on a large cow elk at 53 yds with a 435 gr arrow (9.5 gpi and 125 gr broadhead) set at 65 lbs. I've also had complete pass throughs on good bulls at 40 yds with a 450 gr fmj (.400 spine set at 70 # draw weight) with a 100 gr broadhead. Back then I didn't care about FOC. Today, I want a little more FOC and speed. KE, if it means anything (and it doesn't really), is comparable to a lot of these heavier or "elk hunting weight arrows".

It is difficult to get a higher FOC with fmj's without getting superheavy and killing the mechanical efficiency of your bow. In your case in wanting to keep your current arrow setup and good penetration, I'd look at a different broadhead design (125 gr maybe?) and not chase FOC.

What is your draw length? You have said what your arrow length is, but what is your draw length?

HDE, X2

ElkNut1

ElkNut1

You DO realize that arrow shaft weight forward technology is purposed for arrow flight improvements by changing the spine of the shaft?

The sole purpose is to control the oscillations of the shaft in flight, and has absolutely nothing to do with FOC. In fact, if you research the shafts used by Olympic archers, you will find that they are barrel shaped with the bulk of the shaft being focused in the center of the shaft, not at the ends.

Again, and I can't stress this enough, From a science standpoint, it doesn't matter where the weight/mass is located along the shaft. It only matters that the arrow flight is optimal, and that the spine of the shaft is strong enough for both launch, and entry into the target.

Nobody with a 30" draw length should ever be sold .400 shafts in my opinion.

Having said that, we still don't know what your bows draw length is. It is possible that YOU have a 28.5" draw length, but were sold a 29.5" draw length bow. It's possible you can simply cut an inch or two off your existing arrows, put on 125 grain heads without sacrificing spine integrity.

That still doesn't answer though what your bow is set at for DL. If it was true to your DL, you would be drawing your arrow tip to the rest mounting hole area of your riser at full draw. In which case you would not be able to cut your arrows any shorter, or go to 125 grain head on your 340's.

Pick a fairly stiff arrow so that it will work for the rest of the test.

Pick an arrow weight. Maybe 500 grains. All arrows should have the same exit velocity and KE.

Try to use the same field tips to insure that they are all the same shape and sharpness.

Use different front inserts, rear inserts, and trimmer string to adjust the FOC.

Try for 5, 10, 15, 20, and 25% FOC.

Pick a medium. Ballistic gel may be the best. But any new archery target should work.

Shoot 5 shots with each FOC. If the penetration is not consistent, try again. Maybe you hit a weak spot in the target. Record the individual penetration for all 5 arrows in the group.

That test should eliminate a lot of variables and come pretty close to measuring the effect of FOC on penetration.

ElkNut1

Maybe I'm misunderstanding you, if so I apologize. Am I off track here with your thinking? (grin)

ElkNut1

Again, that's just speculation. Not trying to start an argument here, but you haven't done that testing that I'm aware of. I have, and it requires moving a weighted insert to locations from just behind the point insert to just in front of the arrows center. It made no difference in penetration for me.

With a weight of say 100 grains started at dead center and moved in 1 inch increments to just behind the insert there should be some changes noted...in theory. ElkNut1 prove it out for us.

None that I'm aware of unless you believe in the FOC stuff.

No changes in penetration that we could measure. Speed was constant. The only change I could think of was dynamic spine, but I didn't have any means to test that. Static spine changed some as well as we moved the weight towards the center. The reason why the test is invalid from a science standpoint.

The only way we could reduce as many of the "other" variables was to drop the arrows vertically from the top of our silo into sand and foam. That kept the dynamic spine out of the equation(not being launched from a bow). Again, not a perfect test, but as close as any other I've seen or read.

I've put more thought and research into this subject than any other. When I owned my own archery shop I had access to any and every shaft out there. I could not come up with any combinations that had the same everything except FOC. It's just not possible with existing products to test ONLY a changed FOC without changing other variables.

I did similar testing and noted the same results in terms of penetration, noted very little if any.

More weight only, not FOC equaled deeper penetration. However I was pleasantly surprised in tighter groups.

Removing the fletching will tell a lot in terms of FOC. At least it did in my tests.

Im getting deeper penetration because of weight, Im getting better accuracy because of FOC. My thoughts on this is the arrow is correcting faster out of the bow and side winds if any have little to no effect on flight. I now shoot with straight fletches.

What we can do is test different set-ups with different FOC that all fly well from the same bow and see the results. With all the variables needed to get those arrows tuned with different FOC, we can't determine that FOC was for sure the reason for penetration differences. It could come from one of the other variables or a combination.

The good news is very few people are carrying a bow and arrow combination that won't reliably give great penetration on North American game with the right broadhead. I shoot a slow longbow and always expect an exit.

I don't know what the results would be. I was trying to propose a test that could conclusively prove it one way or another.

Regardless, he has removed the controllable variables.

It's been a good thread and educational for many to, I'm sure. You will always have some instances of "real world" experience and science clashing. Some will only believe what they believe they see and others will only accept the physics.

When you should get suspicious is when someone tells you that 2 + 2 = 5 because they had it happen to them.

It does not incorporate the sudden accelaration which could drastically affect the outcome. So, the results show exactly what they should.

The outcome of that test would be the same if the weight were forward or in the middle.

I wonder what would happen if an insert were glued in the center of the arrow with weights stacked in it then shot from a 70# draw wt bow? Be interesting anyway.

The arrow does know, however, that it has sudden accelaration when the bow string is released. Otherwise, arrow spine wouldn't mean squat. Because of that the arrow will behave differently in flight and impact. I'd wager that the arrow dropped from the height of the silo test wouldn't penetrate and elk laying on it's side the way it will when shot from a bow.

It does matter, really.

Common sense tells you the stiffer arrow will react better out of a a compound on the shot AND on contact with something hard.

But I bet the facts and lack of definitive tests haven't changed any of the EFOC guys minds....

This EFOC stuff has been repeated so many times it has becomes urban legend. Top experts, pros and arrow companies agree that FOC in the 8% to low teens is the way to go- why would someone go against that quality advice...to make a name for themself?

Have you been reading all the posts?

It's been quite obvious that noone wants to change their arrow building prowess for the better, which is our personal decision that thankfully our socialistic gov't has taken away from us but.....

Trax, IF, giant if, you want to, you could use about a 3-4 footing to increase spine, strength and keep your 340s.

This wouldn't be an option for Trax as his long draw length doesn't allow for enough room between the rest and the end of the shaft at full draw.

You don't need to be in the low teens, you don't even really need to consider FOC. It's a non factor.Your experience proves that. 45 years of killing stuff with a bow and not until I started reading archery Forums on the internet was FOC even a thought. The believers can theorize all they want, I suppose it makes for interesting discussion but little else.

your 9.9% will work just fine on Elk, I would give much more in fact all my focus on type and quality of broadhead, and accuracy. If you can hit what you're aiming at and the broadhead is sharp and tough, What you're FOC is, isn't going to change the outcome, you will shoot right through an Elk like he was made of air.

I agree, 250 fps is 250 fps, but is the arrow going that fast when dropped from a height of say 90'? If it is, then the test shows something, if not, then it's missing something.

Yes, x-man, I have been reading the posts, but I may have missed something already pointed out. Care to show me where it was discussed?

No, any change in elevation, no matter how smooth the transition will be the same result as if moving the rest up or down. When tuning a compound bow to have same POI with BH's and FP's that rest elevation adjustment is critical.

I footed almost every Axis arrow shaft that I sold out of my shop. Not for the FOC, but for better seating to the BH. Two inches is/was pretty much the max length as to not interfere with the rest. I don't believe two inches has much affect on spine. Whatever stiffness it may impart to static spine would be negated by dynamic spine at launch.

It's likely too late for your current arrows, but you can install two HIT inserts and achieve a stiffer arrow.

He would get into the teens for FOC as well. It would be a little heavier than footing which in my opinion would be a benefit and it would stiffen his spine. This would also address x-mans thoughts on issues with the rest.

That's exactly how we adjusted the weight location in our test arrows. Except we used brass inserts and glued them in at different locations.

I think I might even have one or two of those still around..... My sons have destroyed most of them shooting rabbits and squirrels.

At 63# draw weight your finished total arrow weight with field tip/broadhead should be 63X6.5- 410 grains at the lightest & do not exceed this weight, 63X7 - 440 grains. Anywhere in that Ballpark & you will do very well on your Deer & Elk hunts. Of course a hair over isn't a big deal but stay within the parameters & you will have an ideal arrow weight for the power your 63# limbs produce!

Here's a photo of 3 arrows shot from a 65# Hoyt compound, top arrow is 429 grains (axis), 2nd arrow (fmj) is 469 grains & 3rd arrow is 472 grains(fmj)-- Notice the lighter 429 grain arrow has out penetrated the other two heavier arrows, all have 100 grain field points & stock aluminum inserts & no extra tubes or anything.

The heavier arrows I tested in those 4-5 sheets of cement board the less penetration I received & when I went lighter on the arrows than the 429 grain one the less penetration I received. This is why I say stay with your arrows that are closest to the 440 grain mark!

ElkNut1

I agree with the point you are trying to make.

The only real reason however, that your axis out penetrated the two FMJ's is because of shaft OD. If your 429 grain arrow was also a FMJ, the results would have been different than what we see in that pic.

ElkNut1

Your compound bow, and others, is light years ahead of my 71# recurve in propelling an arrow, correct?

How is it that, from my bow, a 800ish gainer will, by far, out penetrate a 500 grainer, in any medium I can ever remember hitting.... While your bow does just the opposite. I am missing an important link here that I would like to learn.

FMJ- .340 - 11.3 GPI 30.25 length = 342 grains

Nock, Insert & 3 - 2" Flethings + 40 grains

100 grain field tip = 100

Total = 482 grains

This is why I suggested your 2nd arrow choice of 9.5 or 9.9 ? Not sure which you have but at any rate it would be a better choice for you considering all around balanced arrow! 9.9 GPI at 30.25 = 300 grains -- This would shed 42 grains off your 482 grain FMJ arrow & put you at 442 grains.

ElkNut1

I use the half out inserts made by firenock on my FMJ's rather than the HIT inserts.You can buy them in steel or aluminum. Makes for a very durable strong end of the shaft. I also use epoxy not superglue. Epoxy wont break loose on hard impacts.

ElkNut1

ElkNut1

Yes, nock, flethings & aluminum insert are aprox 40 grains total with stock equipment. Thanks!

p.s. the photos show the different gains. I do have tons more if you need further verification.

ElkNut1

Good luck with that!

i think it has to be something like a hide with 2" of ballistic gel then sheet of concrete sheetrock finally a chunk of ballistic gel about 18" thick.

I've posted the above pic before; this is a 560 gr arrow and the arrow that killed the bull [little red hole] was 840gr....from the same bow.

This pretty much tells the story for me on big critters. On deer size game...just about anything works.

But yet Elknut's "420" grainer is optimum for penetration?

IMO, the shaft diameters probably are more of a factor in stopping an arrow in a backyard... all I can find to shoot... medium, than it does in a lubricated, between the skin, animal.

I've said before there is an optimum of speed and weight for a bow to maximize penetration, but someone else thought differntly...

Shooting a heavier arrow doesn't necessarily mean you will shoot deeper into something just like new shoes won't necessarily make you run faster.

There is, however, a range of arrow weights that will do good for any setup.

May I ask what pound bow are you shooting & what is your arrow weight? Thanks!

Sapcut, why do you refer to a 420 grain arrow as an end all? I never stated that? You shoot a Recurve & don't appreciate the difference between them & compounds. There's a huge difference!

HDE, exactly!

It's funny that some ask for proof, I show it & because it doesn't agree with their thoughts they are quick to dismiss them! There's no pleasing some of you, you are hung in your thoughts & ways & do not care about proof. (grin)

ElkNut1

Respectfully, If I'm not mistaken, you have stated over and over that 420 is the optimum weight for your 66# bow. That makes no sense at all to me regarding penetration on animals. Like I said, regardless of what bow propels it....my slow moving 600 grainer does not penetrate near like my even slower 800 grainer, If I launched a 500 grainer it would penetrate even worse because it would stop quicker even though it would be flying at over 200 fps.

I do think with any bow, at some point the arrow can be too heavy resulting in notsogood inefficient penetration.(not to mention undesirable trajectory) However, that is one end of the spectrum that I have never heard of or seen anyone close. However most are very close to the other end of the efficiency spectrum.

"You shoot a Recurve & don't appreciate the difference between them & compounds. There's a huge difference!"

What? You better believe I do. Its pretty easy to see what a powerful arrow propelling machine it is. I think I appreciate them more than you. It seems to me that you don't think a 66# compound will propel a tuned 600+ grain arrow and penetrate very efficiently. That is hogwash. If a 700 grainer flys at 180ish fps and destroys bone matter, what could possibly be so inefficient about the same arrow flying at 200+ fps"?

"It's funny that some ask for proof, I show it..."

Respectfully, your efforts are commendable but I am very surprised that you would utter the word "proof" regarding your testing efforts. So many holes in it and a couple you continue to totally ignore. It would be a stretch for most bowsiters to suggest Ashby's 25 years of much better arrow testing as proof and you seriously say yours is proof?

"....because it doesn't agree with their thoughts they are quick to dismiss them!"

I may be totally wrong here, and that is perfectly ok, but it looks like that may be what you are doing. You continue to show your optimum 420 arrow appearing to be penetrating more than others while totally ingnoring the importance that it is a micro diameter shaft.

BTW, I seriously mean no disrespect. Just responding to your statements.

From everything I have seen in 30 years of playing with bows....the heavier arrows get better penetration on game.

I've seen many backyard tests out there and there is no doubt in my mind that some skew for different criteria, for example; Short compact BH's perform well in the steel barrel test.....but does that short wedge blade [that pushes] give you the best cutting in an animal?

Agreed, an arrow can be too heavy as it can be too light according to ones draw weight! I have plenty of photos of that too! (grin)

No doubt as I stated above to GotBowAz that a 600 grain arrow can penetrate very good out of a 66# compound. Not sure where you feel I think otherwise? I assume you did not read that post, it's up above. But, the bottom line is a 465 grain arrow with 243 grains up front out penetrated his 600 grain arrow in testing. Why? I also wrote that. It's because the heavy 23% FOC on the VAP arrow was lighter and traveled faster thus out penetrating the 600 grain arrow with the exact head weight but not the exact FOC. Why would one choose the 600 grain arrow when the 465 grain arrow did better & at 135 grains less thus giving you a flatter/faster shooting arrow?

I'm not comparing my efforts to Ashby, I'm merely testing different arrows at various weights & sharing the conclusions, you are more than welcome to snub them but it doesn't change the outcome of the results, please feel free to test as I have & share them with us! Thanks!

Please look at the photo above with the two identical VAP shafts, one is 440 grains & the other 415 grains, (14 posts up) neither did better than the 429 grain Axis shaft. Why, one is a bit light & the other is a bit heavy with the same head weights at 65#. This is after 3 shot groups not one shot & photos. Again, it was the end result. Should I assume that a 600 grain arrow with the same field tip weight would now miraculously be the winner when the 440 grain one lagged behind?

Just food for thought! Yes, I tested 600 grain arrows with 100 & 125 grain field tips & they did not fare well.

Please look at this photo, the upper Victory arrow is the fattest shaft at 390 grains total with 200 grain total head weight, the 2nd Axis arrow is 429 grains with 125 head & 16 grain aluminum insert, it's the winner. The 3rd shaft is a FMJ at 519 grains total, it has a 125 grain tip & 17 grain aluminum insert. This is at 30 yards. Which arrow would you choose on your elk hunt?

ElkNut1

It's not there.

EN has suggested repeatedly to do your own testing, still nothing but lip service from sapcut.

I am also not interested in creating conflict with elknut or anyone else over arrow testing.

Not 100% apples to apples, but at least water, as a test medium acts the same for every shot. FWIW, the 2216 arrow floats vertically with about 4" of tail sticking out of the water. The Beman arrow sank to the bottom, but with the tail end of the arrow floating about 8" off the bottom.

Even knowing, without a shadow of a doubt, the answer to the above questions, people will continue to go in their backyards and work hard at proving why the arrows that currently sit in their quivers are the best penetrating option.

I am also not interested in creating conflict with elknut or anyone else over arrow testing."

Really? b/c thats exactly what you've done and your inability to decipher trad from compound continues to plague your sophomoric thoughts on the subject. In conclusion you're pretty much a troll. Prove your ideas physically, not theoretically, instead of riding the backs of others.

Xman, take that 2216 and fill it w/ water. I wonder how much the buoyancy of those arrows effected their penetration.

Funny the kettle is trying to call the pot black. Repeatedly EN basically said if you don't like his test do one of your own, of which you've not, though you continue to challenge him regarding his test.

BTW, I won't be buffalo hunting anytime soon so I really don't have a clue what you are spouting off about using light arrows and backyard testing....

"You mean riding the backs of others" ?

And yes, Im not surprised, you are one of those.

Some will be surprised at the outcome as several here said there is no difference in penetration with varying FOC's with equal weight & identical arrows! Let's just see!

Beendare, if I were hunting Cape Buffalo I personally would do some serious testing with various arrows, inserts & head weight & I'm pretty sure none would come out on top with a 100 grain head! (grin) Great looking bull!

Using water as medium does not carry over into game animals, that's a whole different animal! (grin) Pretty sure if I shot a 1500 grain arrow out of 66# bow it would literally bounce of a single sheet of 3/4" plywood. (big grin) Right poundage, right arrow! One thing at a time though, I'll share photos in a minute! Thanks!

ElkNut1

Again, all arrows paper tuned, it was easy as I've hunted with these in the past. All arrows exact length, 3 are Axis 340 spine, the 4th is the VAP 420 grain 350 spine, I couldn't resist to see how the VAP stacked up against the 500 grain arrows!(grin) Same 66# Energy Elite 32 bow, all shots 25 yards.

#1- Axis 340 spine 500 grains, 100 grain tip & 17 grain stock aluminum insert, 117 grains. Weight tube 80 grains to make weight. 11 FOC. No pass through! Penetrated 1-1/8" deep.

#2- Axis 340 spine 500 grains, 145 grain tip & stock 17 grain aluminum insert, 162 grains. Weight tube 38 grains to make weight. 15 FOC, No pass through. Penetrated 1-5/8" deep.

#3- Axis 340 spine 500 grains, 125 grain tip & 75 grain brass insert, 200 grains. No weight tube needed. 18.5 FOC, No pass through but dimpled 3rd sheet 3/8" trying to break through. 2-1/8" penetration.

#4- VAP 350 spine 420 grains, 100 grain tip & 92 grain steel insert, 192 grains. No weight tube. Field tip sticking completely out of 3rd sheet along with partial outsert. 16.6 FOC. Full penetration, 3/4" sticking through.

Does FOC help? You bet it does! The 18.5 FOC arrow bested the 11 FOC arrow by 1". That means it passed through a 3/4 piece of plywood & another 1/4" one over the 11 FOC arrow. That's some serious penetration when many here felt they would be fairly equal, tests don't lie! I did two test shot groups & was going to do a 3rd but it started raining, 2 was enough as it was nearly identical to the first round. That's when I decided to shoot the VAP for grins. Glad I did so I could see where my elk arrow stacks up!

Follow the arrow into target with orange nock, that's the VAP arrow, you can see the field tip sticking through, it's the only one that is!

Some will question how the 420 grain VAP could out penetrate all 3- 500 grain arrows, it's because of the balanced FOC & speed combination propelling the heavy FOC arrow faster at 420 grains which turn into added penetration. A 500 grain arrow is heavier & slower out of 66#. Raise your poundage & you can raise arrow weight but take serious consideration you guys building a balanced elk arrow & raise your FOC, it will pay off in the end.

For Deer & Elk like critters stick to that 6.5 to 7 grains X your draw weight & you'll do very well with a finished arrow.

ElkNut1

ElkNut1

ElkNut1

As a side note I bet that tests in virgin foam would be fairly similar to your OSB media tests with the same four arrows as far as penetration ranking. Kurt

Too, the .166 diameter VAP is not going to increase penetration more than 3/8" tops, if that. It just isn't that big of a deal. If you & others feel it is then I'd encourage those to shoot skinnier shafts! (grin)

ElkNut1

A buddy talked me into some of the heavy aluminum fish arrows as they are discontinued. I used them for awhile but was losing a lot of fish that normally would be pounded by my Yellowjacket arrows.

I weighed the aluminums- 800gr finished....where the Yellowjackets are in the 1500-1600gr range....well no wonder.

ElkNut1

Better leave the testing to the younger guys

Wow...won't even beat that on the trad side...lol.

And I'm a trad guy :^)

Here's a better view of the only field point sticking through the 3 sheets!

ElkNut1

I bet its tuning..... and the one light arrow had better arrow flight.

One thing is an absolute fact in archery; an arrow with poor flight will not penetration as well.

That picture makes me feel even more sorry for male homosexuals.

No doubt a heavier arrow is needed when shooting fish in lakes & such. But game animals have structure, we need to get through resistance such as hair, skin, meat, bone, organs, etc. These require an arrow tailored for this type of resistance. Balancing arrow weight to draw weight insures us the best tool for the job.

If I were to up my poundage to 70# plus, the 500 grain arrows would now pass my VAP arrow if left the same as it is. I'd have to re-think my arrow weight for the VAP to keep up.

In testing, if I shot too light an arrow the penetration suffered the same as a too heavy an arrow when met with resistance as we would encounter in a game animal.

I've shown photos of too heavy an arrow for 66#, here's a photo of too light an arrow, the one lagging behind by several inches is a 390 grain arrow at 30 yards. The better penetration was had by a 429 grain arrow. The light arrow shed energy at impact while the better suited arrow for the draw weight maintained energy & momentum.

ElkNut1

I don't see one of those hunts in my future though! (grim)

ElkNut1

If I was going to shoot a totally different trad setup specially picked out for the Jaquomo Unit 7 Invitational, I would probably try a 35-40# 3-piece longbow with about a 400 gr. arrow and highest FOC I could muster which at that weight probably no more than 15% FOC.

If I was going to shoot a compound, I don't know, I guess maybe I would get comfortable shooting something like a 50# bow with 500-600 gr. arrows.

And raw penetration is not even needed at a 3D shoot.

BTW...Is 800 grains super heavy? perhaps for a 50# bow but I don't think it is for a 71# recurve drawing 31.25".

And yes, 800 grains is "super-heavy" unless you are hunting something not found on our continent. Theres a reason why competitive shooters don't shoot 800 grain arrows to achieve optimum accuracy at unknown distances.

There is such a thing as overall balance between arrow weight, arrow flight, broadhead integrity, FOC, and accuracy for optimum hunting performance. Too much of one or not enough of another compromises a hunter's success potential. A very famous, highly-respected and successful trad hunter and writer (who you all know but I won't mention his name) told me a couple weeks ago, "We sure killed a lot of big animals before we ever knew what FOC was..."

To answer your question...Yes, you are correct I would not be as accurate as the competetion in that 3D target shoot. When my desire is to win the $20,000 I would switch gears and would not shoot the heavy bow and arrow. I would switch to the other option I mentioned, 35-40# target bow with lighter arrows. It would be much easier to shoot the 50th shot of the course. Not as easy to do with 71#s. "Theres a reason why competitive shooters don't shoot 800 grain arrows to achieve optimum accuracy at unknown distances"

Absolutely. Because for the same reasons I just mentioned. They don't shoot near the bow weight to satisfy their trajectory demands and most don't have near the stamina to pull the bow confidently thru the course. But then again the objective is not to penetrate target bones. I have never implied target shooters should shoot heavy bows or arrows.

For my setup, I don't think 800 grains is super heavy. My determined arrow weight has nothing to do with what is needed to "KILL" an animal by penetrating the rib cage of any animal. Any weight arrow will do that. I don't want any part of an animal to stop my arrow from killig it. Not always the case but what I strive for.

Heavy arrows and high FOC is not NEEDED to KILL an animal, which is what eveyone goes back to. But it can be the difference in getting thru the most difficult resistance when a lighter one will not. That is why I, ME, choose it.

To each each his own. Dr. Ashby didn't factor accuracy into his studies....

I couldn't shoot a 500 grain arrow accurately from my bow if I wanted to. My bow would feel like it would explode.

There certainly are more accurate shooters out there than I with their lighter big game setups but I will say I did head shoot a grouse this year at 13-15 yards and killed a nice 11 point buck with a 14ish yard running shot as he was chasing a doe.

I'm not giving up accuracy when hunting and I'm also not hunting with a target bow and arrows. Which scenario do you think is more balanced?

ElkNut1

Using the scientific definitions, higher FOC may make an arrow shoot with more precision, but the more radical parabolic arc that increasing arrow weight produces makes it inherently less accurate. As distance increases, any movement at the bow is magnified. Distance estimation just adds to the problem.

I'm trying to put together a little penetration test of my own. I hope to have some data in a day or two.

However, I did drop my arrow weight down to about 770 grains for elk hunting for that exact reason. I think that will help with longer 30-35 yard shots, should I feel I have one.

Isn't it kinda hard to miss with rangefinders and sights? Even your arrow trajectory doesn't matter. Just zero your sights in.

ElkNut1

ElkNut1

Elkman, that's very good, I'm right in there at 16.6 with a total arrow weight of 420, it does well.

ElkNut1

ElkNut1

Purdue the key to your point must be the increased arrow mass....correct? Since F=mg

Because conversely if sapcut shot 2 arrows identical in overall mass, but with different FOCs, they would still both experience the same gravitational force thus decelerating at the same rate creating identical parabolic arcs, and ultimately comparable accuracy...(neglecting friction/air resistance however)

Incorrect. A high FOC arrow is much more forgiving and does not veer off course due to the slightest interference. Not sensitve. A much lower FOC is less forgiving and will veer off course easier.

That is why when you hear someone bareshaft an arrow that is weak, for instance, they say it will kick left and hit right of target. A high FOC arrow may kick left if weak but will correct immediately and hit the target.

At least that is what happens in my case and what I meant by being more accurate and consistent.

"Chronic, Incorrect. A high FOC arrow is much more forgiving and does not veer off course due to the slightest interference. Not sensitve. A much lower FOC is less forgiving and will veer off course easier.

That is why when you hear someone bareshaft an arrow that is weak, for instance, they say it will kick left and hit right of target. A high FOC arrow may kick left if weak but will correct immediately and hit the target.

At least that is what happens in my case and what I meant by being more accurate and consistent. "

That is so wrong, I can't even begin to believe you wrote that. MAYBE with your trad gear, but certainly not with modern compound archery equipment.

Just perhaps you may want to consider building an arrow like I'm speaking of and see what happens.

Yoga pants and HDE's link/idea to weight his arrows with fudge.

As you can see from the photo, they did not tune the same in my bow. When the 5% FOC arrow was in tune the 17% FOC was significantly out of tune. Different setups will be required for each arrow.

ElkNut1, you say your bow is tuned. Can you provide paper tune photos of shots from about 5' and 11' (riser to paper per Easton Tuning Guide) with arrows of identical weight yet significantly different FOC? I don't know why mine would show such a difference yet yours does not. Maybe it's not as in tune as you think and maybe it is. ?????

Me too, that's exactly the shade of lipstick I like to see .... in my paper tear slots. Thanks Purdue! :)

Very profound statement, one setup does not necessarily trump another.

The five shot average penetration of the low FOC arrow was 8.94".

The five shot average penetration of the higher FOC arrow was 9.09".

A difference of .15" or 1.68 % more penetration for the higher FOC arrow.

It appears from this test and from ElkNut1's tests that the faster the arrow decelerate, the greater the benefit of a higher FOC (everything else equal). Bone hit on the near side of an animal would show more benefit from higher FOC than bone hit on the far side of the animal, after the arrow had slowed down.

This stands to reason since there would be less energy robbing shaft flex with the higher FOC arrow during rapid deceleration and little flex (benefit) during slow deceleration.

I"ll try to run some more tests next week on a target that offers more rapid deceleration. (or) Perhaps shooting through plywood after the arrow has passed through 4"-6" of foam.

I'd be interested to know what shafts were uses, how you achieved the different FOC numbers, and the testing criteria for determining the static and dynamic spine deflection of each arrow after the desired FOC was implemented.

I have not been able to isolate [only] FOC in my exhaustive, extensive research. It would be kind of you to share how you were able to do so, thanks.

Nothing against Purdue or any of the other testers but how can a few arrows be considered as something to hang your hat on?

Devils advocate here but; What if there is a softer spot in your test media? What about a minor form error on the shot?

As xman so accurately points out; There are too many variables to isolate just the FOC component.

Heck I've been paper tuning and played with varying my grip a little to see what is going on and a minor change can take me from bullet hole to a 1" tear......THAT is a factor for sure....and its the reason I setup my hunting bows to be as forgiving as possible.

Point being, your high FOC arrow may have been underspined, or you have form issues. As long as the finished spine is correct FOC has little to any bearing on your tune.

But the test was too small. Repeat it 5 times. Record all 15 results (3 arrows x 5 shots each). Those numbers will help determine if the FOC difference is really real.

This is what I was asking Purdue about.

But the test was too small. Repeat it 5 times. Record all 15 results (3 arrows x 5 shots each). Those numbers will help determine if the FOC difference is really real.

No test is perfect. However, this test was more controlled than any of Ashby's or ElkNut1's tests. A more that 300 % increase in FOC yielded only a 1.7 % increase in penetration. You can blame that on a flawed test if you want. I have no dog in the fight. Take from it what you want. Obviously different bows, arrows, FOC, etc. will give different results.

I have no way to directly measure the static or dynamic spine. I don't see that it matters anyway. The point of the test was to see the effect of FOC on penetration in a soft target without the arrow exiting the target material and without adding additional weight. Changing FOC changes the dynamic spine. Those changes are at the heart of the test and is what I was actually testing; the effect of changes in dynamic spine, upon impact, that changes in FOC brings about. It's those very changes in dynamic spine that causes the energy lose that results in the penetration differences. Why would I want them to be constant?

Xman, if you want the static spine to remain unchanged, do not make the internal weight out of one rigid piece. Make it from several short cyclinders who's length is about the same as its diameter so the weight "bends" with the arrow.

I'm interested to see if purdue's testing yields similar results, so far yes.

If I had the time and resources I'd shoot 2 bows same velocity, different FOC, proper spine, same weight and diameter arrow into ballistic gel. FOC difference of 10% minimum, more would be better. So ~10% vs 20%+ FOC.

1.7% may be significant relative to the test medium. Purdue, what was you ES and median for each subject?

The five shot average penetration of the higher FOC arrow was 9.09"."

How variable were the data within each 5 shot group? It is likely that the penetration was not statistically different.

Per Purdue comments arrow weight was identical the only thing that changed was foc.

Low FOC Penetration Data: 9.000”, 9.250”, 9.125”, 9.125”, 8.937”

Low FOC Average Penetration: 8.937”

High FOC: 16.974 %

High FOC Penetration Data: 9.000”, 8.875”, 8.937”, 8.937”, 8.937”

High FOC Average Penetration: 9.087”

Difference in High and Low FOC Penetration: 0.15”

Percentage Increase in FOC of High FOC Arrow: 376.9 %

Percentage Increase in Penetration of High FOC Arrow: 1.68 %

Again real slow. The...arrows...for...both...tests...weighed...the...same.

It's never ceases to amaze me how people read in or read out their preconceived notions. People also only want to listen to those that support their preexisting point of view. This applies to politics, religion, archery and most everything.

This test does not prove that FOC is effective or ineffective. It only shows what it shows....what it did under these conditions. I suspect that high FOC will do better under rapid deceleration like when it hits plywood instead of foam. ElkNut1's tests seem to indicate this, but also IMO seem to exaggerate the difference. Just my opinion, it all has yet to be demonstrated under a controlled test. Perhaps the difference will even be greater that ElkNut1's test show.

Might want to check... ;)

It should be correct now.

Thanks, HDE.

Specifically, what did you use inside your arrow for weight? How much did it weigh?, and what did you use to glue it in? What shaft was used(ex. Beman Hunter 340)? Draw weight? arrow speed? total arrow weight?

Curious minds want to know

A tenth of an inch increase in foam board is a fair amount for same weight arrows. Would be interesting to see how 25-30% foc would compare.

God Bless men

Really! seems hardly worth moving on

I question the medium as whether or not it is a good representation to evaluate our intended purposes. Like I said, the difference [in penetration] may be more substantial in a different medium yielding more significant findings. Lets face it, a target designed to stop arrows is a far cry from a blood filled hair bag, which leads me again back to ballistics gel due to its flesh-like uniformed consistency.

Another question pops in my head. Yes we are trying to decide FOC's effect on penetration which requires all variables minimized such as velocity and weight primarily. BUT in the real world an archer will not need to maintain these constraints and as FOC is increased chances are weight will increase and consequently velocity will decrease unless the archer has a plethora of arrows to optimize his rig. I for one do not.