M3A1 “Grease Gun” submachine gun
Designed by George Hyde c.1942 and manufactured by Guide Lamp - General Motors - c.1943~50′s.
.45ACP 30-round magazine, open bolt blowback full automatic, stamped sheet metal construction, hinged bolt dust cover.
Designed to replace the Thompson submachine guns as a cheaper alternative, it failed to enter a big enough production rate to achieve that. It still remained in service until the 1990′s as a vehicle crew weapon.