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Atmospheric Pressure Affect Velocity?
- Thread starter Bigwheels
- Start date
Re: Atmospheric Pressure Affect Velocity?
No not at the muzzle. There is just less drag, so your bullet won't slow down as fast.
No not at the muzzle. There is just less drag, so your bullet won't slow down as fast.
Re: Atmospheric Pressure Affect Velocity?
Reason I'm asking is I did some work @ SL, & chrony's @ 2800 fps. with virgin brass, but when I went to 5500" ASL with once fired brass I chrony'd 2820 fps.(I have a tight chamber) I didn't think I was useing 20 fps of energy to expand the new brass. I could be wrong, &/or my chrony was screwing with me.
Reason I'm asking is I did some work @ SL, & chrony's @ 2800 fps. with virgin brass, but when I went to 5500" ASL with once fired brass I chrony'd 2820 fps.(I have a tight chamber) I didn't think I was useing 20 fps of energy to expand the new brass. I could be wrong, &/or my chrony was screwing with me.
Re: Atmospheric Pressure Affect Velocity?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MALLARD</div><div class="ubbcode-body">skyking how do you know ? </div></div>
Simple physics. Atmospheric pressure is essentially air density so a projectile moving through a lower density fluid receives less drag amplitude than a higher density fluid. Yes, the Earth's atmosphere is a fluid. It's entirely possible that the reduced pressure in the barrel gave it that 20fps of extra speed, but as skyking said, the most obvious difference is going to be the overall trajectory of the bullet at higher altitude.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MALLARD</div><div class="ubbcode-body">skyking how do you know ? </div></div>
Simple physics. Atmospheric pressure is essentially air density so a projectile moving through a lower density fluid receives less drag amplitude than a higher density fluid. Yes, the Earth's atmosphere is a fluid. It's entirely possible that the reduced pressure in the barrel gave it that 20fps of extra speed, but as skyking said, the most obvious difference is going to be the overall trajectory of the bullet at higher altitude.
