Thompson M1928A1
Auto-Ordnance Corporation · Submachine Gun · Out Of Production · 1940
Also known as: Tommy Gun, Thompson Gun, Chicago Typewriter, Trench Broom, Chopper, The Annihilator, M1928A1 SMG
Overview
The Thompson M1928A1 is the military-standard variant of John T. Thompson's iconic .45 ACP submachine gun, adopted by the U.S. Army in 1938 and mass-produced from 1940 to 1942 by Auto-Ordnance and Savage Arms to arm American and Allied forces in the opening years of World War II. Evolved from the commercial M1921 and Navy M1928 models, the M1928A1 retained the retractable Blish-lock actuator, finned cooling barrel, Cutts compensator, and top-mounted charging handle that gave the weapon its unmistakable profile -- while accepting both 20- and 30-round stick magazines and the legendary 50- and 100-round drums. Chambered for the hard-hitting .45 ACP cartridge and firing from a closed bolt at roughly 700 rounds per minute, the M1928A1 delivered devastating close-range firepower prized by Marine Raiders, British Commandos, paratroopers, tank crews, and squad leaders alike. Its heft (nearly 5 kg empty, closer to 6 kg fully kitted with a loaded drum) blunted recoil and anchored its reputation for controllable full-auto fire, but also made the gun expensive, slow to produce, and awkward to carry -- shortcomings that would drive the wartime simplifications of the M1 and M1A1 variants.
Specifications
| Weight (empty) | 4900 g (172.8 oz) |
| Weight (loaded) | 5400 g (190.5 oz) |
| Overall Length | 857 mm (33.74") |
| Barrel Length | 267 mm (10.51") |
| Height | 150 mm (5.91") |
| Width | 60 mm (2.36") |
| Action Type | Blowback |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Stage |
| Magazine Capacity | 50 rounds |
| Magazine Type | Drum |
| Muzzle Velocity | 280 m/s (919 fps) |
| Muzzle Energy | 585 J (431 ft·lbf) |
| Effective Range | 150 m (164 yd) |
| Maximum Range | 1500 m (1640 yd) |
| Rate of Fire | 700 rpm |
| Barrel Rifling | Right Hand |
| Rifling Twist | 406 mm (15.98") |
| 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 Automatic Colt Pistol, 11.43x23mm
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine, Drum Magazine
- Safety mechanisms: Manual Fire Selector, Manual Safety, Bolt Lock
- Features: Select Fire, Closed Bolt Operation, Blish Lock Actuator, Finned Barrel, Cutts Compensator, Adjustable Ladder Rear Sight, Top Mounted Charging Handle, Pistol Grip Foregrip, Removable Buttstock
Variants
- Thompson M1921 — Original Commercial
- Thompson M1923 — Military Trial
- Thompson M1927 — Semi Automatic Civilian
- Thompson M1928 Navy — Naval Predecessor
- Thompson M1 — Simplified
- Thompson M1A1 — Simplified
Base model
Service history
Operators
- United States Army · adopted 1938 · as M1928A1
- United States Marine Corps · adopted 1928 · as M1928
- United States Navy · adopted 1928 · as M1928 Navy
- United States Coast Guard · adopted 1930 · as M1928
- Federal Bureau of Investigation · adopted 1934 · as Thompson
- British Commandos · adopted 1940 · as Thompson
- British Armed Forces · adopted 1940 · as Thompson
- Special Operations Executive · adopted 1940 · as Thompson
- Canadian Armed Forces · adopted 1940 · as Thompson
- Australian Defence Force · adopted 1940 · as Thompson
- New Zealand Armed Forces · adopted 1940 · as Thompson
- Soviet Red Army · adopted 1941 · as Thompson
- National Revolutionary Army · adopted 1940 · as Thompson
- French Resistance · adopted 1942 · as Thompson
- Irish Republican Army · adopted 1921 · as Thompson
- Royal Ulster Constabulary · adopted 1922 · as Thompson
- Philippine Commonwealth Army · adopted 1941 · as Thompson
- Yugoslav Partisans · adopted 1942 · as Thompson
Conflicts
- Irish War of Independence (1919-1921)
- Irish Civil War (1922-1923)
- Banana Wars (1898-1934)
- Prohibition-era Gang Wars (1920-1933)
- Second Sino-Japanese War (1937-1945)
- World War II (1939-1945)
- Chinese Civil War (1927-1949)
- Greek Civil War (1946-1949)
- First Indochina War (1946-1954)
- Korean War (1950-1953)
- Vietnam War (1955-1975)
Production
Estimated total produced: 562,511 · Production years: 1940-1942
Auto-Ordnance produced approximately 562,511 M1928A1s between 1940 and 1942 across its own Bridgeport facility and its contractor Savage Arms in Utica, before the design was superseded by the simplified M1. Total WWII Thompson production across all variants (M1928A1, M1, M1A1) exceeded 1.7 million units.
Origin
Country of origin: United States
Designer: John T. Thompson
Discontinued: 1942
Notes
The M1928A1 is distinguished from the earlier M1928 Navy model chiefly by a horizontal forearm (replacing the front pistol grip on many examples), a military-spec sling swivel configuration, and parkerized or blued finishes in place of commercial bluing. Although Auto-Ordnance retained the Blish lock -- a bronze H-shaped friction piece theorized by Commander John Blish to retard bolt opening under pressure -- Army testing during the war demonstrated the mechanism contributed nothing to function, and it was deleted in the subsequent M1. The drum magazines, while iconic, rattled loudly on patrol, were heavy, slow to load, and prone to jamming; frontline troops generally preferred 20- or 30-round stick magazines, and U.S. Army drums were officially discontinued for field use in 1942. Wartime production was split between Auto-Ordnance's Bridgeport, Connecticut facility (using tooling from Colt's original 1921 contract run) and Savage Arms in Utica, New York, which ultimately produced the majority of WWII Thompsons. By 1942 the M1928A1 had been superseded in production by the simplified M1, but existing M1928A1s remained in widespread frontline service throughout the war and into Korea.
Background
Before the Tommy Gun stormed the beaches of Guadalcanal, it stormed the speakeasies of Chicago: seven men lined against a North Side garage wall on Saint Valentine's Day 1929 were killed by Thompsons wielded by Capone's disguised gunmen, and the massacre cemented the weapon's outlaw mythology in a single afternoon. Conceived by General John T. Thompson as a WWI 'trench broom' to sweep German infantry out of fortified positions, the gun arrived months too late for the war it was built for -- so its first paying customers were the Irish Republican Army, Prohibition bootleggers, and the FBI agents hunting them. When the Blish-lock principle -- the whole theoretical justification for the design -- was quietly exposed as metallurgical snake oil during wartime testing, engineers simply removed the bronze H-piece and the gun kept running exactly as before.