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muzzle velocity and temperature


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#1 qtztwn

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Posted 03 December 2010 - 02:45 PM

Has anyone taken a particular rifle, a chronograph, and several brands of 22 ammo and measured the change in muzzle velocity with ambient temperature?

#2 aack73

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Posted 03 December 2010 - 05:50 PM

Has anyone taken a particular rifle, a chronograph, and several brands of 22 ammo and measured the change in muzzle velocity with ambient temperature?

I have an old chronograph that used to measure paint ball guns. i was gonna get it out and try it on one ofmy rifles. don't know if its the same as or as good as what most would use to crono a gun but it was cheap enough and i'm going to experiment with it some. i'm curious as to how if any how the velocity changes as the gun barrel heats up but not to the point of toasting my barrel.lol :huh:
i'm sure somebody on here probably has it graphed out or has a link to it. this place is the rimfire encyclopedia.

#3 Technical Director

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Posted 04 December 2010 - 11:37 AM

Has anyone taken a particular rifle, a chronograph, and several brands of 22 ammo and measured the change in muzzle velocity with ambient temperature?



Recently, one of my range buddies was trying out a new chronograph. To establish a bench mark regarding the accuracy of it's calibration, he/we shot some 22 lr's over it, as the velocity of the 22lr was posted on the side of the box. To our surpise, the extreme spread of the 22 velocity was plus of minus 20fps, however excluding the extreme spread it was more so plus or minus 5 fps. This was with only one brand of 22 lr bulk ammo not sure what you would find with others or with target grade 22 ammo.

Hope this smattering of information helps, Technical Director

#4 qtztwn

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Posted 04 December 2010 - 12:11 PM

John Barsness (AR, Aug 09) looked into this for high-velocity high-power ammo and depending on the type of powder, he found that it ranged from a change of nearly 8 fps per degree F down to virtually nil. Even a rumored value of 2 fps per degree F, would make a significant difference if one were sighted in at a 100 yards at 70 degrees one afternoon and went out in the morning a few days later at 20 degrees. This could mean a drop of 100 fps which would translate to drop of 1.25 inches at 100 yards and that is not counting the temperature effect on air density.




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