Range Report DA vs Muzzle Velocity

[cavemanmoore]

Maybe a dumb question, but my little brain needs help. If I chronograph a load when density altitude is 1000', then re-chronograph the same load when density altitude is 10,000', will the velocity be different?

Thanks,
-Chris

 

[The Mechanic]

Re: DA vs Muzzle Velocity

That would depend totally on how far away you are taking the measurement.

 

[cavemanmoore]

Re: DA vs Muzzle Velocity

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: The Mechanic</div><div class="ubbcode-body">That would depend totally on how far away you are taking the measurement. </div></div>

10' from the muzzle.

Thanks for the reply,
-Chris

 

[The Mechanic]

Re: DA vs Muzzle Velocity

Than not enough to really notice. There just is not enough time when you are a few feet away from the muzzle for air density to effect the bullet.

 

[Niles Coyote]

Re: DA vs Muzzle Velocity

The muzzle velocity should remain the same unless the ammo is exposed to the elements and heats or cools from the temperature they were when you did your initial velocity check.

Flight characteristics will be different for various DA’s

 

[one shot ST]

Re: DA vs Muzzle Velocity

As Lindy wrote the only factor to take in account is how your load/powder is temperature sensible.

I do in this manner, 10 cartridges in the freezer overnight, put them in a refrigerated bag with a kestrel and I go to the shooting range, shoot and chrono, for example I find and average muzzle velocity of 800 m/s with average temperature of -5 C.

second step is shoot and chrono 10 cartridges at ambient temperature, for example I find 815 m/s and 25 C

now I do 815 - 800, the spread is 15 and the spread between 25 and -5 is 30 C, now 15/30 and the result is 0.5.......so every degrees I've an sum/subtract 0.5 m/s and this the only thing I need