Type	Submachine gun
Place of origin	United States

Service history

In service	1941–1953
Wars	World War II Hukbalahap Rebellion Malayan Emergency Costa Rican Civil War Vietnam War

Production history

Designer	Eugene Reising
Designed	1940
Manufacturer	Harrington & Richardson
Produced	1941–1945

Specifications

Mass	3.1 kg (6.83 lb) (M50) 2.8 kg (6.2 lb) (M55)
Length	959 mm (37.8 in) 787 mm (31.0 in) stock retracted (M55)
Barrel length	279 mm (11.0 in) (M50)
Cartridge	.45 ACP
Action	Delayed blowback, closed bolt
Rate of fire	550 rounds/min (M50) 500 rounds/min (M55)
Muzzle velocity	280 m/s (919 ft/s)
Maximum firing range	300 yards
Feed system	12- or 20-round detachable box magazine, 30-round aftermarket detachable box magazine
Sights	Front blade, rear notch