The 280 MM Gun At The Nevada Proving Ground

Courtesy National Nuclear Security Administration / Nevada Site Office The 280 MM Gun at the Nevada Proving Ground 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. This was the only nuclear artillery shell ever actually fired in the US test program. The shell was 1384 mm (4.5 ft) long and weighed 365 kg (805 lb); it was fired from a special artillery piece, nicknamed “Atomic Annie“, built by the Artillery Test Unit of Fort Sill, Oklahoma. Around 3,200 personnel were present. The warhead was designated the W9 and 80 were produced from 1952-53 for the T-124 shell. It was retired in 1957.