Arrow flight at higher altitude
Equipment
When a bow is sited in at lower elevation, is there much difference when you go up to 8-12000ft ?
Yea Forsure there can be a difference from sea level to 12,000
Huge for me when shooting lighter arrows. Ask the 2 prongys that I shot over their backs in high elevation Nevada. Randy Ulmer says best way to compensate is by dropping draw weight. That way you don’t need to adjust individual pins.
Way too many variables to give a definitive answer, but yes the difference is real. Temperature affects air density too, just as elevation affects it. Higher temps as well as high elevation mean less dense air, and a slightly higher shooting arrow, especially at longer ranges. Who produces the best arrow ballistic tables taking into account the "BC"...ballistic co-efficient of your arrow that includes inputs like vanes, wrap, arrow shaft, FOC, tip, outsert, etc? Of course the other inputs would include air temp, elevation and starting velocity of the chosen arrow.
I notice a slight difference and I sight in at around 5800 ft. and hunt around 10000 ft, ex. at 80 yards I had about a 3 inch rise from 5800 ft to 10000ft elev. I really started to pay attention when I realized what a difference in ballistics it was for my bullet drop/rise with my rifle. But also humidity and temperature will play a factor as well. For instance if you sight in at low elevation with high humidity and hunt in a dryer climate at higher elevation, you will see a difference..
COHOYT is correct, humidity...H2O vapor...actually makes air less dense as gaseous water molecules replace the denser air molecules which is about 80% N2 and 20% O2 if I remember my mine ventilation calcs correctly and would have an effect.
The simple way to calibrate your bow for all these variables would be to have a device that measured absolute barometric pressure (14.7 psi at sea level under standard conditions) where you were shooting (might be 10 psi up at 10,500' where you find your elk). You could input that number into your ballistics calculator instead of air temperature and humidity, plus elevation. Luckily for hunting ranges for most of us with a limited effective maximum range, this level of detail isn't required to make a killing shot on an elk or sheep. That said, shoot your bow around the elevation you are hunting at if it is quite different from home to see if you need to adjust draw weight or move the sight a bit to bring the zero back in.
i'll never be a good enough shot to notice.
Bou, me too. I live at 600 ft and have killed at 11500. Maybe an inch at 50 yards?
I do keep my bows below 280fps.
Most guys won't notice with archery equipment unless making longer shots. But lots of variables; temp, humidity, baro pressure, altitude, wind, ballistic coefficient.. it really makes a difference in long range bullet ballistics.. if memory serves me correctly, a 10 degree temperature difference at 1000 yards could be like 10 MOA change, so that's 100 inch difference drop or rise, now add in another variable like humidity or baro change and everything gets all screwy. but bottom line is, if you take a target with you to where you hunt and r double check your zero (rifle or bow) and make adjustments where needed you'll be good to go.
Just to think, for all these years I’ve been blaming myself for missing a 20-yard shot with my longbow at a bighorn ram at 12,800’!
And all along it was the altitude;^)
It makes such a huge difference that I don't recommend coming to high elevation to hunt if you live below about 3,000 feet. Between the lack of oxygen, altitude sickness, arrow flight differences, exacerbated alcohol effect, and reduced vehicle performance, you'll have a bad time. Better to stay home and hunt where these problems aren't issues.
Jaq x 2 ... my friends from the Midwest wont come to hunt anymore because arrow flight becomes so bad and too difficult to account for and fix in short period of time.. that and all the fires.. its a good year to stay home for sure..
Good lord Jaq, I agree we should just give up! Its not that big of a deal with a bow. Cohoyt...thats a big deal on the rifle. I have never adjusted a rifle more than 2 moa with 8000'elevation change.
Don't forget the lower gravity at altitude. Maybe a 0.0000004% reduction.
I live at 8,000' and when I went to Michigan, which is just a few feet, I did not notice a difference in the distances I was shooting at the sketchy whitetail deer there. They still jumped the string and ducked the arrow from 30 yards to 60 yards. So I had to limit my shots to 25 and under.
3-4 inches is a huge difference in my opinion.
I have found that the lighter and the faster the arrow speed, the greater the altitude height affects the flight. When we first heard of this, we tested it to see its effects and was quite surprised. There were 5 of us and we were camped at around 10,000 ft. We came from an altitude of 4,400 ft where we had all sighed in. When we setup the target at camp, we found all of us were shooting 1.5 to 2.5 inches high at 20 yards. The variation was due to arrow weight and arrow speed, not the make of the bows. Since then, I have always taken a target up on the mountain to do the final sight in prior to the opening of the hunt. I have always had to reset the sight pins once I return back home. If you are shooting at speeds below 280 fps, likely you will not see much of a difference.
My opinion on the matter, if you're asking the question, you probably aren't a good enough shot to be shooting far enough for it to matter! Just check your bow when you get to where you're going.
I live at 4,600 and have hunted at 10,000 at least 20 times with at least 10 different guys who live here or lower and no one has ever experienced 1.5” to 2.5” difference at 20 yards. 40 to 50, maybe; but 20? It ain’t happening!
Tilz... depends on your setup... and it does happen. I live at 4,400 feet and I hunt every year at 10,000 ft and it happens every year to all of us.
1.5 to 2 inches isn't much and most hunters don't shoot well enough to see that difference at hunting camp using broad heads. They just figure that if they can shoot a 4 inch group, that is good enough to kill their quarry, which it is... after all, there aren't "12 point spots" painted on a deer or elk, but the question was asked and the answer is, "yes", altitude does affect arrow flight. How much will vary with the hunters setup. We were told about it one year at camp, so we tested it. You obviously haven't tested it. I challenge you to find out rather than make a blanket statement. For those who shoot outdoor 3-d competitions at various elevations, shooting at a 12 ring, it is a big deal to them. You can bet they sight in and make changes prior to every competition, especially when they are changing altitudes. For many years we attributed high shots to wind, uneven ground or even broadheads, but since we were hitting within the kill zone, it didn't matter much. Over the years, I have over shot more animals than I have under shot at longer distances. I still miss, but not as often and in those cases, it is nerves more often than altitude. I would suggest that you do as we did, heard about it so we tested it, then you will know how much your bow and arrow setup is affected at altitude and you can make the needed adjustment if you feel the need.
2" becomes a factor when shooting steep angles.
Yes, hence why it is wise to take a target with you and continue practicing to stay fresh and make those minor adjustments. I finalize my pins at 9,000 feet and shoot from 20-100 yards.
Allen keys and a judo point or two! Never leave home without em.
Don't forget to slide your peep as well. Reduced gravity allows your spine to relax and you become taller as you go up the mountain. People don't think I'm that tall in Winnipeg at sea level, but you should see me in Denver.
I watched a show years ago where a "famous TV hunter" shot over the back of an elk at about 30 yards and blamed it on the elevation difference from "back home" (obviously somewhere in the south).
his elevation problem was the elevation he held his sight at not the elevation his boots were on.
X2 “I have found that the lighter and the faster the arrow speed, the greater the altitude height affects the flight”
This is an astute observation which would be hard to detect with archery equipment. In ballistics one would typically expect increased ballistic coefficiency at elevation thus flying better which would increase the bullets trajectory. This would be due the change in the barometric pressure. Elevation and temperature would have the greatest effects with humidity having negligible overall impact. This would be magnified over distance. Potentially this change could up to 2” moa. So 2 inches high at 100, 4 at 200, 6 at 300 so you get the idea. This should correlate to an arrows flight but there would be many variables involved.
Slower heavy arrows shot at 20 yards would have much less effect versus a much faster lighter arrow at 60 or 70 yards. Typically this change should be uniform so I could see maybe dropping the elevation bar should make a uniform shift of elevation bar should make the correction. Individual pin adjustment should not come into play. Maybe you would only notice as the distance significantly increases at say 40,50, 60, or 70 yards. Only the better shots would notice would notice at 20 or thirty yards. Obviously, sea level to ten thousand feet would be a great deviation. I have noticed a slight change with an arrow going from sea level to 7500 feet.
It is a minimal change but it is real. There is no way it is 3" at 20 yards though. My guess is maybe a couple inches at 80 or so max?
When you take a shot at 12,000' the arrow goes way, way out, out into outer space.
Do you have to have a license for outer space?
Yeah, you need a license or the Space Force Wardens will write you a ticket!
I definitely noticed a slight difference, sighted my bow around 950ft elevation, had to re-sight all my pins at 9,000ft the day before the season. Not a huge difference but obviously exaggerated as you get further away. Bring a target with you...
You mean I gotta go way down there to the low country and re-sight my bow at 9K!!!!???
Maybe that was my problem...
Hopefully sighting in down there in the low country will help when I finally get in range of that fat muley buck at 12,000’!
Now, how in the world am I gonna figure out how to sight in for hunting antelope at 6,000’?
I like it...... next goat I whiff at 7-8000 I can just say "shucks, forgot I sighted in right at sea level...." Sounds much better than "I never saw that stick....."
There's a 1-1/2" difference at 60 yards, between my house and the range in Eugene, 150 miles away. Eastern OR. vs western, from 3,600' to 400'.
I had a problem with arrows shooting low on an antelope hunt in northern Colorado once. I was hitting a plate at 60 yds in Ks before I left and had to completely re sight in my bow in Colorado after I missed a pronghorn
