The M3 grease gun

The M3 is an American .45-calibersubmachine gun adopted by the U.S. Army on 12 December 1942, as the United States Submachine Gun, Cal. .45, M3.

The M3 was chambered for the same .45 ACP round fired by the Thompson submachine gun, but was cheaper to mass produce and lighter, at the expense of accuracy. The M3 was commonly referred to as the "Grease Gun" or simply "the Greaser," owing to its visual similarity to the mechanic's tool.

The M3 was intended as a replacement for the Thompson submachine gun, and began to enter frontline service by mid-1944. By late 1944, the M3A1 variant was introduced, which also saw use in the Korean War and later conflicts.

Origin: United States, 1943

Manufacturer(s): Guide Lamp Division of General Motors, Ithaca Gun Company

Caliber: .45 ACP, 9x19mm Parabellum

Action: Open Bolt, Blow Back

Rate of Fire: 450rpm

Weight: 8.18lbs

Barrel Length: 7.99 inches