US Primer, Percussion, M31




This 150-grain primer is used with supercharged rounds for 75mm guns, its higher capacity being necessary for efficient ignition of the larger amount of smokeless powder in the supercharge. The primer is entirely similar to the M22A1 Primer, except that the flash tube is without vents to such a distance from the head as is necessary to accommodate 150 grains of black powder. It is of later design than the M22 Primer which accounts for its having the later design of priming head, although it is unmodified.

See Also

Primer, Percussion, M22, M22A1, M22A2, M22A3


TM 9-1904, Ammunition Inspection Guide (1944)