| 120mm gun M1 | |
|---|---|
 120 mm M1 anti-aircraft gun at US Army Ordnance Museum | |
| Type | Anti-aircraft gun |
| Place of origin | United States |
| Service history | |
| In service | 1944–1960 |
| Used by | U.S. Army |
| Wars | World War II Korean War |
| Specifications | |
| Mass | 64,000 lb (29,000 kg) |
| Length | 24½ feet (7.39 m) |
| Barrel length | 23½ feet (7.16 m) |
| Crew | 13 (gun commander, gunner with eight man squad, ammunition chief supervising two ammunition handlers) |
| Shell | 120 × 775 mm R |
| Shell weight | 50 lb (22.7 kilograms) |
| Caliber | 120 mm L/60 |
| Barrels | 1 |
| Breech | Vertical sliding-wedge |
| Recoil | Hydro-pneumatic |
| Carriage | towed |
| Elevation | 80 degrees |
| Traverse | 360 degrees |
| Rate of fire | 12 rpm |
| Muzzle velocity | 3,100 ft/s (945 m/s) |
| Maximum firing range | 82,000 ft (25,000 m), 57,500 ft (17,500 m) maximum altitude |
The 120 mm gun M1 was the United States Army's standard super-heavy anti-aircraft gun during World War II and the Korean War, complementing the smaller and more mobile M2 90 mm gun in service. Its maximum altitude was about 60,000 ft (18,000 m), which earned it the nickname stratosphere gun.
The M1 gun was used by the Army for air defense from 1944 to 1960, serving primarily in static defensive roles, although it had been designed to be mobile. It became obsolete with the development of anti-aircraft missiles and was phased out after 1954. However, a derivative mounted in the M103 tank served in that capacity until 1974.