Thompson M1921
Auto-Ordnance · Submachine Gun · Discontinued · 1921
Also known as: Tommy Gun, M1921 Thompson, Annihilator, Chicago Typewriter
Overview
The Thompson M1921 is an American .45 ACP submachine gun and the first production model of the Thompson, designed by General John T. Thompson and produced for the Auto-Ordnance Corporation by Colt. It used the Blish friction-delayed blowback action, a finned barrel, vertical foregrip and detachable wooden buttstock, and fed from 20- or 30-round box magazines or 50- and 100-round drums. Finely machined and expensive to build, it fired at a high cyclic rate of around 800 rounds per minute and became infamous as the 'Tommy Gun' during the Prohibition era.
Specifications
| Weight (empty) | 4880 g (172.1 oz) |
| Overall Length | 857 mm (33.74") |
| Barrel Length | 267 mm (10.51") |
| Action Type | Delayed Blowback |
| Firing Mechanism | Hammer Fired |
| Magazine Capacity | 50 rounds |
| Magazine Type | Drum |
| Muzzle Velocity | 280 m/s (919 fps) |
| Effective Range | 150 m (164 yd) |
| Rate of Fire | 800 rpm |
| Barrel Rifling | Right Hand |
| Number of Grooves | 6 |
| Frame Material | Steel |
| Barrel Material | Steel |
| Stock Material | Wood |
| Finish | Blued |
Calibers
- .45 ACP · primary — also known as .45 Auto, 45 ACP, 11.43x23mm
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine, Drum Magazine
- Safety mechanisms: Manual Safety, Fire Selector
- Features: Blish Lock, Finned Barrel, Vertical Foregrip, Detachable Buttstock, Lyman Adjustable Sights, Compensator
Variants
- Thompson M1921AC — Compensated
- Thompson M1928 — Reduced Rate
Service history
Operators
- United States Marine Corps · adopted 1921
- United States Postal Inspection Service · adopted 1921
- Irish Republican Army · adopted 1921
Conflicts
- Irish War of Independence (1919-1921)
- Prohibition-era gang violence (1921-1933)
Production
Estimated total produced: 15,000 · Production years: 1921-1922
Approximately 15,000 M1921 units produced by Colt for Auto-Ordnance; sold slowly due to high cost and limited civilian/military demand.
Origin
Country of origin: United States
Designer: John T. Thompson
Discontinued: 1928
Notes
Roughly 15,000 M1921 guns were manufactured by Colt under contract for Auto-Ordnance in 1921. The high cyclic rate and machined construction were later toned down in the M1928 and simplified for wartime production in the M1928A1 and M1.
Background
Marketed before any major military order, the M1921 found early buyers among the U.S. Marine Corps, police forces, and notably the Irish Republican Army, before gaining lasting notoriety in the hands of Prohibition-era gangsters who earned it the nickname 'Tommy Gun.'