M3 submachine gun

Submachine Gun, Cal. .45, M3
World War II–era Guide Lamp M3 submachine gun with 30-round magazine and other accessories. The Buffalo Arms bolt in this original M3 is dated January 1944.
Type	Submachine gun
Place of origin	United States
Service history
In service	1943–present
Used by	See Users
Wars	World War II[1] Chinese Civil War Greek Civil War[2] Indonesian National Revolution First Indochina War[3] Korean War[1] Cuban Revolution Algerian War Bay of Pigs Invasion[4] Vietnam War[1] The Troubles Laotian Civil War Malayan Emergency Sino-Indian War Communist insurgency in Malaysia (1968–1989) Papua Conflict Rhodesian Bush War Cambodian Civil War Turkish invasion of Cyprus[5] Shaba II[6] Cambodian–Vietnamese War Sino-Vietnamese War Salvadoran Civil War Argentine Dirty War Falklands War[7] Soviet–Afghan War Iran–Iraq War[8] Persian Gulf War[9] Moro conflict Burundi Civil War Kosovo War First Ambon riots[10] War in Afghanistan Iraq War[citation needed] Syrian Civil War [citation needed]
Production history
Designer	George Hyde
Designed	1942
Manufacturer	General Motors, others
Unit cost	Approx. US$15 (1943; equivalent to $264 in 2023)[11]
Produced	1943–1945 early 1950s
No. built	Total: 655,363 M3: 606,694 M3A1: 48,669
Variants	M3A1 PAM1 PAM2 T29
Specifications
Mass	M3 (empty): 8.15 lb (3.70 kg) M3A1 (empty): 7.95 lb (3.61 kg)
Length	29.1 in (740 mm) stock extended / 21.9 in (556.3 mm) stock collapsed
Barrel length	8 in (203.2 mm)
Cartridge	.45 ACP (11.43×23 mm) 9×19mm Parabellum .30 Carbine (7.62x33mm)
Action	Blowback, open bolt
Rate of fire	450 rounds/min cyclic (= 7½ / second)
Muzzle velocity	900 ft/s (274 m/s)
Effective firing range	Sights fixed to 100 yards (91 m)[12]
Feed system	30-round detachable box or 32-round detachable box magazine
Sights	Fixed rear peep sight and blade foresight, calibrated to 100 yards for caliber .45 M1911 ball ammunition[12]

The M3 is an American .45-caliber submachine gun adopted by the U.S. Army on 12 December 1942, as the United States Submachine Gun, Cal. .45, M3.^[12] 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.^[12] The M3 was commonly referred to as the "Grease Gun" or simply "the Greaser," owing to its visual similarity to the mechanic's tool.^[13]

The M3 was intended as a replacement for the Thompson, and began to enter frontline service in mid-1944. The M3A1 variant was used in the Korean War and later conflicts.

The M14 rifle, adopted in 1959, was intended to replace the M3A1 (as well as the M1 Garand, M1918 Browning Automatic Rifle and the M1 carbine)^[14] but the recoil of the M14's 7.62×51mm NATO cartridge proved too powerful for the submachine gun role. The M14 was in turn replaced by the M16 rifle in 1964, and this weapon (firing the intermediate 5.56×45mm NATO cartridge) was a better replacement for the M3A1. M3A1 submachine guns were retired from U.S. frontline service after 1959, but continued to be issued, for example as backup weapons for armored vehicle crews as late as the Gulf War (1990-1991). Many overseas US military bases continued to issue these for certain crews into the mid to late 1990s.^{[citation needed]}