M1 - A simplified version of the M1928 model, designed to reduce the cost of production in wartime. Released in 1942. It had an automatic blowback, a loading handle on the right side of the receiver, a wooden forearm, a barrel without fins and a compensator. only used with box magazines, fixed rear sight. An even more simplified version of the M1A1 model 1943 had a fixed drummer instead of a movable one.