M855


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kestak
December 8, 2012, 03:40 PM
Here we go again....

Developping a new load because I got a bunch of brand new M855 bullets. I plan to shoot those exclusively into my SIG556. Anyone developped a load that is close to the military load with WC844 currently sold by hitech ammo (they have the same lot since about one year and half) or Ramshot TAC?:D

In bonus anyone developped that load with one of those piwders for the SIG556? :D

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Walkalong
December 8, 2012, 05:23 PM
I haven't shot any 62 Gr bullets with TAC, either lead core or M855 style, in my 556 Classic.

I have shot 55 Gr bullets in both my 16" ARs and my 16" 556 Classic, and the velocities were very close. The loads cycled the 556 just as well as the ARs, although the 556 ejects brass much more energetically, leading me to believe a lower powdered round would still cycle in it when the AR would start short stroking. I cannot prove that, it just seems logical.

NeuseRvrRat
December 8, 2012, 08:40 PM
MIL-C-63989C
CARTRIDGE, 5.56MM, BALL, M855

3.6 Velocity. The average velocity of the cartridges,
conditioned at 70 +/- 2F, shall be 3000 feet per second (fps) plus or minus 40 fps at 78 feet from the
muzzle of the weapon. The standard deviation of the velocities shall not exceed 40 fps.

3.7 Chamber pressure. The average chamber pressure of the sample cartridges, conditioned at 70 +/- 2F shall not exceed 55,000 psi. Neither the chamber pressure of an individual sample test cartridge nor the average chamber pressure plus three standard deviations of chamber pressure shall exceed 61,000 psi.

3.8 Port Pressure. The mean port pressure minus three
standard deviations shall not be less than 12,700 psi for sample cartridge conditioned to 70 +/- 2F.

3.10 Temperature stability. The action time, pressure and velocity of sample cartridges conditioned and fired at the temperature extremes specified below shall be in accordance with 3.10.1, 3.10.2, 3.10.3, and 3.10.4

a. Conditioned at 125 +/- 2F for not less than one hour and fired at that temperature.
b. Conditioned at -65 +/- 2F for not less than one hour and fired at that temperature



there's what the military requires of M855. you're gonna need some expensive equipment to make sure your handloads match.

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