Developed as a companion piece for the Thompson Submachine Gun, the Thompson-Peters 45 Auto Shot Cartridge combined a double-crimped 45 ACP casing with a cardboard sabot loaded with #8 birdshot. Loaded into a special magazine, the cartridge was compatible with an otherwise factory standard Thompson SMG, and marketed as a less-lethal weapon for riot control and prison management. All three magazines are blue finished and bear three-line, three-date patent markings on the front, two marked "FOR 18 SHOT CARTRIDGES" and one marked "FOR SHOT CARTRIDGES".

Good overall. One of the "18" marked magazines has a dent on the front that affects follower travel, and the "FOR SHOT" magazine has shallow pitting and signs of cleaning with steel wool.