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Old October 14, 2011, 09:38 PM   #14
Slamfire
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Join Date: May 27, 2007
Posts: 4,108
The spec values that people quote are very misleading. The military did not publish reloading manuals, the TM’s that people get these numbers were from spec values. What is not understood is that all these velocity and pressure values are traceable to Government acceptance barrels, I assume from Frankfort arsenal.

The 2750 fps +_ 50fps was not tested in Garand barrels but in vendor pressure barrels. Reference cartridges that gave spec values in the Frankfort Arsenal barrel where fired in the vendor barrel and velocities and pressures were “corrected” to the Frankfort Arsenal values. I don’t know the dimensions of that barrel but GI ammunition fired in my barrels is a lot slower, which makes me think the Frankfort Arsenal barrel was of different length.

GI ammunition is not hot, you want to keep your 150 grains velocities in a Garand below 2700 fps.


30-06
M98 26" 1-10 Wilson Barrel


150 gr FMJBT TW 56 Ball
24 Mar 04
T= 70 ° F

Ave Vel = 2680
Std Dev = 31
ES = 78
Low = 2620
High = 2698
N = 6
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