Osprey author Leigh Neville concludes his series examining the small arms used by US forces in the Second World War. This final week he looks at the Thompson sub-machine gun, an iconic SMG that proved as popular with Hollywood and Prohibition era gangsters as it did with the US military.
The Thompson was originally envisioned as a “trench-broom” for use in clearing enemy positions during the First World War. Developed too late t...o see service, the Thompson, then known as the Annihilator, was a conventional blowback fully automatic platform chambered for the .45ACP round then in use with the issue M1911 automatic pistol. Fed from either 20 or later 30 round magazines or 50 or 100 round drums, the Thompson was soon purchased by a number of US federal agencies and the United States Marine Corps.
In 1938, on the cusp of the Second World War, the Thompson was officially adopted across all services as the M1928A1, instantly recognisable by its distinctive Cutts compensator and top mounted cocking handle. Along with US forces, the M1928A1 was issued to many Allied nations including Australian infantry and commando units (many were replaced with the lighter and more reliable 9x19mm Owen when it became available).
The weapon was popular for its firepower, particularly in urban operations, but lacked the range, penetration and kinetic effect of the M1 Garand and similar full power service rifles. It was also criticised for its weight (its wooden ‘furniture’ saw it weigh in at 5 kilograms) and price (in particular in comparison to the stamped metal Sten or M3 ‘Grease Gun’). Again, like the M1 Carbine, many of its detractors failed to appreciate that the Thompson was designed expressly as a, albeit overly heavy, short range personal defence weapon and was competent in this role.
The M1928A1 was supplemented and eventually largely replaced by the M1 and M1A1 variants which simplified the design placing the cocking handle on the right side of the weapon, dispensing with the Cutts compensator, and reducing the weapon’s weight by half a kilogram. The M1 and M1A1 became popular with US forces in Europe and although the M3 and M3A1 ‘Grease Gun’ was procured to replace the Thompson, the M1 and M1A1 soldiered on until war’s end.