M-65 (T-131) Atomic Gun

In 1949 the U.S. Atomic Energy Commission started the development of a nuclear device small enough that it could be incorporated into a 280mm caliber projectile. Shortly thereafter, the Picatinny Arsenal managed to integrate the W-9 15 kiloton warhead into a conventional 280mm T-124 projectile. In May 1950, work began to design a cannon that could fire the new nuclear shell, taking as a basis a 240mm gun created during a former project called T-1. In the late 1950 Watervliet Arsenal completed the design of the 280mm T-131 gun, and in the spring of 1951 the first prototype of the gun mounted on a 280mm Gun Carriage T-72 was completed. Finally, in October 1952 three complete guns were publicly presented at Aberdeen Proving Ground and then production began to complete 20 units until 1953.

M-65 Atomic Gun gallery and more info


Información adicional

Ficha Completa
Country of origin

United States


Picatinny Arsenal


Heavy towed gun

Entered service



7 servers

Combat weight

Gun (without carriage): 19,049 kg – Gun in firing position: 42,582 kg
M.249 front truck: 17,191 kg – M.250 rear truck: 16,267 kg

System weight

Gun + carriage + transporter units: 78,308 kg

Dimensions (length x width x height)

Gun (barrel + breech): 13.02 meters – Barrel: 12.75 meters
M.249 frontal truck: 9.70 x 3.12 x 3.21 meters
M.250 rear truck: 9.66 x 3.12 x 3.49 meters
Travel position: 25.98 x 3.15 x 3.42 meters

Power plant

M.249 & M.250 units: 1 x Continental AO 895.4 air cooled gasoline engine, 375 hp (each unit)

Power, (total)

750 hp


65 km/h


280 km


1 x 280/45.5mm T.131 gun

Shell weight

T.122 HE (conventional): 272 kg – T.124 nuclear: 364 kg – T.315 nuclear: 272 kg

Shell range

T.122 HE (conventional): 28.70 km – T.124 nuclear: 24.75 km – T.315 nuclear: 30.70 km

Muzzle velocity

T.122 HE (conventional): 762 m/s – T.124 nuclear: 628 m/s – T.315 nuclear: 722 m/s

Warhead, (explosive charge)

See photo gallery for details

Yield, (maximum)

T.124 shell: 15 Kilotons – T.315 shell: 15 to 20 Kilotons