"Mobile Nuclear artillery"

"The first artillery test was on May 25, 1953 at the Nevada Test Site. Fired as part of Operation Upshot-Knothole and codenamed Shot GRABLE, a 280 mm (11 inch) shell with a gun-type fission warhead was fired 10,000 m (6.2 miles) and detonated 160 m (525 ft) above the ground with an estimated yield of 15 kilotons.[1] This was the only nuclear artillery shell ever actually fired in the U.S. nuclear weapons test program. The shell was 1384 mm (4.5 ft) long and weighed 365 kg (805 lb). It was fired from a special, very large, artillery piece, nicknamed the "Atomic Annie", built by the Artillery Test Unit of Fort Sill, Oklahoma. About 3,200 soldiers and civilians were present. The warhead was designated the W9 nuclear warhead and 80 were produced in 1952 to 1953 for the T-124 shell. It was retired in 1957.
Development work continued and resulted in the W19. A 280 mm shell, it was a longer version of the W9. Only 80 warheads were produced and the system was retired in 1963 coinciding with the introduction of the W48 warhead."