The 280mm Atomic Cannon Test
The unreal testing of the Atomic Cannon. Yes that's a nuclear gun. On May 25, 1953 at 8:30am local time, the Atomic Cannon was tested at Nevada Test Site (specifically Frenchman Flat) as part of the Upshot-Knothole series of nuclear tests. The test--codenamed Grable--was attended by then Chairman of the Joint Chiefs of Staff Adm. Arthur W. Radford and Secretary of Defense Charles E. Wilson; it resulted in the successful detonation of a 15 kt shell (warhead W9) at a range of 7 miles. This was the first and only nuclear shell to be fired from a cannon. Subsequent to the successful test, there were at least 20 of the cannons manufactured at Watervliet and Watertown Arsenals, at a cost of $800,000. They were deployed overseas to Europe and Korea, often continuously shifted around to avoid being detected and targeted by opposing forces. Due to the size of the apparatus, their limited range, the development of nuclear shells compatible with existing artillery pieces (the W48 for the 155mm and the W33 for the 203mm), and the development of rocket and missile based nuclear artillery, the M65 was effectively obsolete soon after it was deployed. However, it remained a prestige weapon and was not retired until 1963.