Developed in 1942, the M1A1 was the final wartime iteration of the Thompson SMG, with a final round of design changes to further streamline the design and speed production. While a number of bells and whistles were removed, the M1A1 was still a robust and powerful "heavy metal" SMG capable of standing tall among it's tube receiver brethren of the era. Blade front and fixed peep rear sight, with a small "P" stamp on the smooth barrel. A set of "GFC" and "FJA" inspection stamps are present on the front left of the receiver, with "S" (Savage subcontract) on the underside and a set of "RIA" and "FK" stamps for overhaul and re-inspection at Rock Island Arsenal on the left rear, along with the standard nomenclature, caliber and "U.S./PROPERTY" markings. The bolt is the M1A1 pattern, heavyweight with a fixed firing pin, narrow recoil spring, side-mounted charging handle and "AOC" on the rear. The trigger assembly is unnumbered, with a set of selector and safety levers. Fitted with a smooth horizontal forearm, grooved pistol grip and a fixed buttstock.