Just have to shoot them in your setup and decide?
Mine changes because I shoot 100 and 125 grain heads on the same arrows. And I don’t know or care what the FOC is.
Yes, but what KIND of arrows??
The bow I was shooting yesterday tunes for me with either a 340 carbon + 225 grain FP (about 9 GPP and 21% FOC, and I’m hunting with 235 gr BH) or a 2117 aluminum + 175 (8.9 GPP, 16.2% FOC, and BH for this arrow come in at 180-185). I could use a lighter point with a 2018 + 125 (8.3 GPP) but that’s still showing 12.6% FOC in the calculator… Or maybe a 2020 and 135 to get me back up to 9GPP and 12.4% FOC…
To get down to 10%, FOC ain’t easy. I would have to shoot a 1918 aluminum with an 80 grain point (at a rather stupid-light 7.4 GPP, 9.2% FOC) or I could go with a 2020 and 100 gr up front (adding 1.5” in total length) to come out at 8.7 GPP and 9.6% FOC.
But who does that??
Probably nobody, I’m guessing, because the only people who are going to shoot a high-GPI shaft are the guys who are looking for high total GPP.
So unless you are a wood-arrow fan, you would really have to go out of your way to get there. Once you get into more than 14 GPI shafts, you can start hitting 10% FOC pretty easily, like with a 28”, 14 GPI arrow and a 125 gr point (540 gr TAW), and I would bet that more than a few deer have been killed by a combo like that.
FOC is one of those things that I think people place WAY too much importance on.
I still shoot Aluminum shafts, I come out at FOC around 4. They really do fly well !
Just curious— what are your specs for shaft size/length and point weight??
“… there are two dynamic spines involved when shooting at animals; one at launch and one at impact. Increased FOC positively effects both.”
First - I’d definitely agree that dynamic spine upon impact is generally ignored (as in, I think a lot of people know that high FOC is Good, but probably don’t appreciate why) and actually pretty decisive, because a weak spine flexes on impact and once the center of mass of the arrow is no longer behind the point, Bad Things happen. Which is why guys shooting #35 longbows can get a clean pass-through on a deer while guys shooting #50+ compounds can fail to do so….
That said…. If you are properly tuned, isn’t FOC immaterial at launch?
If you don’t agree with that, please do explain…
But I did notice a curious thing when I got to toying with the spine calculator and plugging in higher values for wood shaft densities….
My intuitive sense was that a heavier arrow (GPI) would accelerate more slowly, therefore acting stiffer at a given static spine rating (as occurs when adding weight to the rear) because fewer Gs. But (Duh!) because mass is distributed fairly evenly along the length of the shaft (tapers excluded), adding mass apparently weakens the dynamic spine, whether it’s in the point or anywhere else in the front half…
Which means that the dynamic spine upon impact is weaker, which allows the increased mass of the shaft to wander farther off of the line of initial penetration when provoked, which is going to Do Bad Things. My first forays into bareshaft testing were pretty grim, with overspined arrows snapping right off after hitting a soft target at an unforgiving angle… Coulda saved myself a few bucks just by starting a few steps closer…
Anyway… Guys like elkmtngear are going to do a lot better with a Howard Hill type of broadhead with a mechanical advantage than with anything shorter, wider or otherwise higher-resistance WRT penetration…. Of course, it also helps a lot if you avoid strong bones. ;)
Flight shooters like neutral FOC because (as EMG said) they fly real well…. if they are tuned right… but more FOC is more forgiving, and a few of my Most Learned Mentors have noted that a high FOC arrow is practically half-fletched even as a bare shaft… Plus, Flight shooters don’t give a rip about penetration or probably even whether their arrows survive the one impact, just as long as it flies as far as possible and the judges can find where it landed…. Hunting site, so I’m assuming that most here want an arrow that doesn’t waste any momentum slapping the animal and causing it to run that much harder…
Since then, all of the experts back those numbers
No kidding! But those days are gone. Hardly anybody shoots enough poundage anymore to make that combination work without going to nearly full-length shafts… And even at 30”, that’s still 13% FOC. ;)
Those are my exact specs, with a 27.5 inch shaft, 4 fletch (I fletch my own arrows). I shoot an Elite Pure, 65 pound limbs. Being a finger shooter, I just could never seem to "tame" the carbon arrows, even if I used weight tubes.
Most long time bowhunters cant tell you their FOC…and none of them I know set up their arrows with that in mind.
Considering the uber high FOC guy many listen to “proved” his theory with Rubber bands and soda straws….I think I will listen to the experts- grin
Until we have self-propelled arrows, this is useless data for flight stability. It does however show the uselessness of flex and dynamic spine at the launch.
As with most things in life, the pursuit of UBER or EXTREME usually takes a good idea and ruins it.
Not really. It's the sudden acceleration and deceleration that is the variable of interest, not the stabilized trajectory, so it does matter.
The guys doing these scientific controlled tests went on to be recognized Rocket scientists ( Legit) , they named the space center after Goddard. CN Hickman is in the archery hall of fame for his studies on the science behind archery.
The tests are compiled in a book, “Archery, The Technical side”.
Was that before or after vinyl records went from cylinder to flat disc?
I don't know mine nor care
Elite Synergy set at 52# - GT Hunter XT 340, 28" with standard components and 125 grain head - TAW 421 gr. - FOC = 11.1%.
Elite Enkore 52# - Easton Sonic 340, 28" with 3" feathers and standard components, 125 grain head - TAW 384 gr. - FOC = 15.3%.
You're not taking into account Young's Modulus for wood (arrows) against carbon from recurve to modern compound.
Think I'll tie some cement blocks to the front bumper of my old truck.... should help ?????? ;)
If that was only typed once it could be a typo. Likely just confused with either the 2219 or 2419, which were both available in the XX75 Camo Hunter.
I'm laughing so hard..I'm sorry that's just funny
Coincidence that every top pro in every archery discipline is within the Same range?
Maybe the testing in the early days was with different archery equipment, but the results have been verified over the decades.
FOC on the extreme ends of the spectrum doesn't improve anything, be it approaching Zero or 30%- in fact it's a negative. So whomever is telling you different is a quack.
He used these for everything. Frank and his wife Becky were both world champions back then.
Meaningless related to broadheads and hunting but maybe of interest
I Have heard some crazy stuff from the great target guys...though I don't think it equates to what's best for the rest of us.
I heard Terry Ragsdale talk of setups with very light nibs used back in the day. I've seen the Hoyt rep [a pro shooter back in the day] move his tuned bows rest 3/8" out and shoot multiple arrows in the same hole from 15y. Dwayne Martin told me the year he won Vegas and out shot the compound guys with his recurve with multiple 300 rounds in a row that his arrow wasn't the one with the best tune- best arrow flight. His slightly out of tune setup shot concisely 2 points higher...and thats what he won with.
If it works for you...then go for it.
I guess I tried to duplicate Frank Pearson's and her shooting form.... relaxed and easy. (Only starts arguments but no tension and no surprise shot.) Pearson said if you couldn't shoot as long as you felt like you were shooting too heavy a bow. I did go from 66# to 56# -58# after learning from him. Made a difference.
Pretty certain the Ragsdales were both 1 time mentored by Pearson. Pearson, long before I knew him, was with PSE . Him and Shepley had some kind of bad falling out.
Flex at launch is neither useful or useless — it simply IS. And it’s (strictly speaking) inevitable, so best learn to live with it or make it work for you.
But my theory is Bad arrow flight has caused more wounding and penetration problems than Mech BH's or other arrow factors like FOC. I've seen it many times....and arrow wobbling on its way to an animal, then the hunter blames it on something else.
Nevermind the top target guys may shoot whatever arrow gains them a couple points.....they all definitively state that they wouldn't hunt with that setup, they use a BH tuned arrow to hunt with.
