Judging from the serial number, the gun shown dates from 1941. Auto-Ordnance made 323,900 M1928A1s at Bridgeport, Connecticut, between 19. Some 2 million Thompson guns were made between 19. Of course, it also provides that period feel …
I have fitted mine with an aftermarket forward pistol grip, which is not a perfect replica but pretty close, and allows a good fit given my size and arm length. The M1928A1 normally ‒ but not always ‒ has a horizontal handguard instead of the forward pistol grip. Practically all of these components are missing from the wartime M1 and M1A1 Thompsons. However, the M1928A1 retains most of the original features, including the finned 26.7-cm (10.5”) barrel, Lyman-made Cutts compensator, adjustable Lyman rear sight, detachable shoulder stock, and ability to use drum magazines. It also has the lower cyclic rate of the Model 1928AC and M1928. It differs from the civilian Model 1921AC of 1926 and the Model 1928AC and the US Navy’s M1928 of 1928 in a few cost-cutting measures, including the dull Parkerized finish instead of the blueing of the earlier weapons.
Despite minor variations over the course of the following 17 years, the M1928A1 adopted by the US Army in 1938 is still basically the same gun. The original gun entered production as the Model 1921 in that year, made by Colt’s Patent Fire Arms Manufacturing Company of Hartford, Connecticut, under contract for the Auto-Ordnance Corporation. The Thompson gun was envisioned by John Thompson in 1917, but much of the actual design was performed by Theodore Eickhoff. This a practical review of the Auto-Ordnance M1928A1 Thompson gun, with an eye towards its performance in games like GURPS, Call of Cthulhu, and Delta Green: The Role-Playing Game.