MIL Spec Data for M193 and M855 Ammunition
Last Updated :: 6/21/2010 11:55:18 AM EST
MIL Spec Data for M193 and M855 Ammunition

by AeroE

The following information is excerpted from the MIL-C specs that lay out the qualification tests for M193 and M855 military ball ammunition. The most recent revision (as of Sept 2007) of each spec was referenced.


MIL-C-9963F
CARTRIDGE, 5.56MM, BALL M193

3.6 Velocity. The average velocity of the sample cartridges, conditioned at 70 + 2 Fahrenheit (F), shall be 3165 feet per second (ft/sec) plus or minus 40 ft/sec, at 78 feet from the muzzle of the weapon. The standard deviation of the velocities shall not exceed 40 ft/sec,

3.7 Chamber pressure.

3.7.1 Measurement by copper-crush cylinder. The average chamber pressure
o€ the sample cartridges, conditioned at 70 +/- 2F, shall not exceed 52,000 pounds per square inch (PSI). The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 58,000 PSI.

3.7.2 Measurement by piezoelectric transducer. The average chamber pressure of the sample cartridges, conditioned at 70 + 2F, shall not exceed 55,000 PSI. The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 61,000 PSI.

3.8 Port pressure.

3.8.1 Measurement by copper crush cylinder. The average port pressure of the sample cartridges, conditioned at 70 +/- 2F, shall be 15,000 PSI +/- 2000 PSI.

3.8.2 Measurement by piezoelectric transducer. The average port pressure of the sample cartridges, conditioned at 70 +/- 2F shall be shall be 14,400 PSI +/- 2000 PSI.

3.9 Temperature stability. When the sample cartridges are subjected to the following storage conditions, the average velocity shall not decrease by more than 250 ft/sec and the average chamber pressure by either method used in 3.7 shall not increase by more than 5000 PSI, the average port pressure by either method used in 3.8 shall neither increase nor decrease by more than 2000 PSI with respect to the average velocity, chamber pressure and port pressure of the sample cartridges of the same lot, conditioned at 70 +/- 2 F for a minimum of twenty minutes. Any increases in velocity and decreases in chamber pressure of the sample cartridges under these temperature conditions are acceptable,

Stored at 125 +/- 2F for not less than one hour and fired at that temperature.
Stored at -65 +/- 5F for not less than one hour and fired at that temperature.

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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.

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MIL-C-70460A
CARTRIDGE, 5.56mm, BALL, (HEAVY BULLET) REFERENCE

3.6 Velocity. The average velocity of the cartridges when conditioned at 70 degrees plus or minus 2 degrees Fahrenheit (F) shall be 3,020 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 20 fps.

3.7 Chamber pressure. The average chamber pressure of the sample cartridges, conditioned at 70 degrees plus or minus 2 degrees F, shall not exceed 58,700 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 64,700 psi.

3.8 Port pressure. The mean port pressure minus three standard deviations shall not be less than 15,600 psi for sample cartridges conditioned at 70 degrees plus or minus 2 degrees F.