air temp, altitude, and, air density effects - The Firearms Forum

KonanO · 10-23-2011, 04:15 PM

Hey.. I would like to know if anyone has a suggestion to add to the general formula for Kinetic Energy (stopping power) which would impact on the rise and fall over a 100 yd range independent of grain. It would help on calculating zeroing in independent of the ammo manufacturers.

ie K=1/2 M*V2(.000142)

flyingtiger85 · 10-23-2011, 05:28 PM

Those effects on an airplane are called Density Altitude.You need more speed to get the same effects that you would get at sea level in reguards to lift or rate of climb.It's a real killer of pilots at high elevation airports in the heat of the day.So a bullet at a high altitude would have less resistance and less air molecules effecting it. Which would result in it reaching higher speeds.

Buckshot · 10-24-2011, 03:24 AM

Wow! There may be a Most Esoteric New Question Award in this for you!

I'm sure the question is valid...though I can't say off the top of my head whether the effect is even noticeable enough to matter at 100 yards. Or even 200 or 300.

I know military snipers consider such things for extra long range shots. I would try to find some source for some of their info.

Anyone got any ideas?

Old Grump · 10-24-2011, 12:14 PM

Don't know what to tell you old buddy, as a target shooter the only thing I worried about between 100 and 500 yards was wind and light, (because of using iron sights), After 600 yards humidity, temperature, altitude etc. were added to wind as factors. 100 yards is so close I honestly don't think you would get any meaningful measurements in energy differences. You certainly wont notice any meaningful difference in point of impact in up close and personal shooting at 100 yards except with lower power guns and maybe round nose bullets like a 30-30 or handgun bullets.

10-23-2011, 04:15 PM	#1
KonanO Member Join Date: Oct 2011 Location: Central America Posts: 1	air temp, altitude, and, air density effects Hey.. I would like to know if anyone has a suggestion to add to the general formula for Kinetic Energy (stopping power) which would impact on the rise and fall over a 100 yd range independent of grain. It would help on calculating zeroing in independent of the ammo manufacturers. ie K=1/2 M*V2(.000142) -->

10-23-2011, 05:28 PM	#2
flyingtiger85 Senior Member Join Date: Aug 2010 Location: Nevada Posts: 777	Re: air temp, altitude, and, air density effects Those effects on an airplane are called Density Altitude.You need more speed to get the same effects that you would get at sea level in reguards to lift or rate of climb.It's a real killer of pilots at high elevation airports in the heat of the day.So a bullet at a high altitude would have less resistance and less air molecules effecting it. Which would result in it reaching higher speeds.

10-24-2011, 03:24 AM	#3
Buckshot Senior Member Join Date: May 2009 Location: Southern AZ Posts: 918	Re: air temp, altitude, and, air density effects Wow! There may be a Most Esoteric New Question Award in this for you! I'm sure the question is valid...though I can't say off the top of my head whether the effect is even noticeable enough to matter at 100 yards. Or even 200 or 300. I know military snipers consider such things for extra long range shots. I would try to find some source for some of their info. Anyone got any ideas? __________________ United States of America - Born July 4th, 1776 - Killed by 50 million brain-dead zombies November 6th, 2012 Mack: Shame what this town's come to. Charley Waite: You could do something about it. Mack: What? We're freighters. Ralph here's a shopkeeper. Charley Waite: You're men, ain't you? Mack: I didn't raise my boys just to see 'em killed. Charley Waite: Well you may not know this, but there's things that gnaw at a man worse than dying. - Open Range MOLON LABE

10-24-2011, 12:14 PM	#4
Old Grump Advanced Senior Member Join Date: Feb 2010 Location: Little hut in the woods near Blue River Wisconsin Posts: 2,320	Re: air temp, altitude, and, air density effects Don't know what to tell you old buddy, as a target shooter the only thing I worried about between 100 and 500 yards was wind and light, (because of using iron sights), After 600 yards humidity, temperature, altitude etc. were added to wind as factors. 100 yards is so close I honestly don't think you would get any meaningful measurements in energy differences. You certainly wont notice any meaningful difference in point of impact in up close and personal shooting at 100 yards except with lower power guns and maybe round nose bullets like a 30-30 or handgun bullets. __________________ "When once a republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil."~~- Thomas Jefferson Roman Catholic, Life Member of American Legion, VFW, Wisconsin Libertarian party, Wi-FORCE, WGO, NRA, JPFO, GOA, SAFand CCRKBA