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Bart B. · September 3, 2013, 03:45 PM

oldpapps, your velocity tests with two different barrels and one longer than the other is not a good comparison. I doubt the peak pressure's the same in each one. And their bore, groove and chamber dimensions are probably not the same. Too many other things to change muzzle velocity besides barrel length.

I've clocked the same 7.62 NATO M80 ball load in a near new 22 inch M1A barrel with 200 or so rounds through it and a 26" Win. 70 barrel with over 4000 rounds through it. Muzzle velocities were only 12 fps apart; fastest one was from the M1A barrel with tighter bore and groove dimensions than the Win. barrel.

September 3, 2013, 03:45 PM	#11
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	oldpapps, your velocity tests with two different barrels and one longer than the other is not a good comparison. I doubt the peak pressure's the same in each one. And their bore, groove and chamber dimensions are probably not the same. Too many other things to change muzzle velocity besides barrel length. I've clocked the same 7.62 NATO M80 ball load in a near new 22 inch M1A barrel with 200 or so rounds through it and a 26" Win. 70 barrel with over 4000 rounds through it. Muzzle velocities were only 12 fps apart; fastest one was from the M1A barrel with tighter bore and groove dimensions than the Win. barrel. Last edited by Bart B.; September 3, 2013 at 03:52 PM.