The final wartime revision of the Thompson Submachine Gun, the M1A1 was on paper made obsolete by the M3/M3A1, but would continue to serve as late as the Vietnam War. Blade front and fixed peep rear sights, with a horizontal handguard, and an "S" marked machined receiver with "GEG" military inspector marks and "U.S./PROPERTY" on top. The trigger housing has dual control switches, a fixed buttstock, and a grooved pistol grip. Internals are M1A1 configuration, with a solid bolt body, fixed firing pin, and no provision for a Blish lock or oiler.