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.

Fair, with a mixed refinished blue and brown appearance overall. Some extensive heavy pitting is present overall under the blue on the receiver, with lighter pitting on the barrel, spotting on the trigger housing, and a loose rear sight. The refinished furniture is very good, with some scuffs and dents. Mechanically very good. NOTE: This weapon is a National Firearms Act (NFA), fully transferable Class 3, which is registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives, (BATFE) that is classified as a "Curios or Relic" as defined in 27 CFR, 478.11. These weapons are still subject to the provisions of 18 U.S.C. Chapter 44 and 27 CFR part 478.