I have a 3gun scope that is set for 200yd,285,425 and 525yds. This is at 6300 elevation. I will be shooting the smm3gun match and need to know what my new poi will be with a 69gr SMK going 2894 fps. I belive the elevation is around 1250 but not sure. Any AZ shooters out there. With the other factors being about the same, I know its not but humor me.
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Range Report Change in elevation whats my new poi
- Thread starter showlow50
- Start date
Re: Change in elevation whats my new poi
Make some DA cards from Lindy's instructions, and buy a Kestrel 4000
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/DA/
Make some DA cards from Lindy's instructions, and buy a Kestrel 4000
http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/DA/
Re: Change in elevation whats my new poi
One thing you could do to get a rough estimate of changes in JBM would be to enter (as closely as you can remember) the temperature when you were zeroing at those ranges. You have the altitude and can probably get by with a corrected barometric pressure of 30.00 or so, provided it was a clear, sunny day. (Advantages of these semi-arid to desert climates).
Then get on Google Earth, find the location for the shoot, get the elevation and approximate temperature and substitute those in the appropriate fields. Make sure to check "Pressure is Corrected" since you will be using a corrected pressure with different altitudes. It will get you reasonably close.
Ideally, you'd have precise weather readings (pressure, temp, humidity) and exact altitude when you zero so you can establish a better baseline for future calculations/corrections. A weather meter would be a good investment, but you may have tools already available, such as a car thermometer and a GPS (many will give you barometric pressure - but do need to be calibrated first).
One thing you could do to get a rough estimate of changes in JBM would be to enter (as closely as you can remember) the temperature when you were zeroing at those ranges. You have the altitude and can probably get by with a corrected barometric pressure of 30.00 or so, provided it was a clear, sunny day. (Advantages of these semi-arid to desert climates).
Then get on Google Earth, find the location for the shoot, get the elevation and approximate temperature and substitute those in the appropriate fields. Make sure to check "Pressure is Corrected" since you will be using a corrected pressure with different altitudes. It will get you reasonably close.
Ideally, you'd have precise weather readings (pressure, temp, humidity) and exact altitude when you zero so you can establish a better baseline for future calculations/corrections. A weather meter would be a good investment, but you may have tools already available, such as a car thermometer and a GPS (many will give you barometric pressure - but do need to be calibrated first).
Re: Change in elevation whats my new poi
If you're getting a short-range zero - 100 yards or meters - the only thing worth recording is the temperature. Muzzle velocity is not affected by barometric pressure, altitude, or humidity.
It's not of much use unless you know what the change of muzzle velocity with temperature is. It takes extreme changes in temperature to affect a short-range zero.
It's always worth recording atmospheric conditions when shooting at longer ranges, of course.
If you're getting a short-range zero - 100 yards or meters - the only thing worth recording is the temperature. Muzzle velocity is not affected by barometric pressure, altitude, or humidity.
It's not of much use unless you know what the change of muzzle velocity with temperature is. It takes extreme changes in temperature to affect a short-range zero.
It's always worth recording atmospheric conditions when shooting at longer ranges, of course.
Re: Change in elevation whats my new poi
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">If you're getting a short-range zero - 100 yards or meters - the only thing worth recording is the temperature.</div></div>
Good point. I once asked Jonathan Zdziarski, the author of Ballistic, why there were settings for both a "Zero" and a "Current" atmosphere. I wasn't seeing any difference in my 100-yard drop. He replied that with a 300-yard or greater zero, you would see a difference. I get all the inputs I can because I never go to the range without also shooting at 300 or 600.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">If you're getting a short-range zero - 100 yards or meters - the only thing worth recording is the temperature.</div></div>
Good point. I once asked Jonathan Zdziarski, the author of Ballistic, why there were settings for both a "Zero" and a "Current" atmosphere. I wasn't seeing any difference in my 100-yard drop. He replied that with a 300-yard or greater zero, you would see a difference. I get all the inputs I can because I never go to the range without also shooting at 300 or 600.
Re: Change in elevation whats my new poi
Indeed. The original Barrett M82 came with a base with 60 MOA built in, so a 100 yard zero was not an option. If you're going to zero at longer ranges, then record all the conditions. Some ballistic programs, given the zero range and zero conditions, will compensate for a change from the conditions in which the longer range zero was obtained.
Indeed. The original Barrett M82 came with a base with 60 MOA built in, so a 100 yard zero was not an option. If you're going to zero at longer ranges, then record all the conditions. Some ballistic programs, given the zero range and zero conditions, will compensate for a change from the conditions in which the longer range zero was obtained.
