Atomic Annie: The US Army's Only Nuclear Artillery Fired 68 Years Ago

May 25, 1953, is a historic day for the US Army. This was the day when the Army successfully fired the M65 atomic cannon at its Nevada test site in the midst of the Cold War. 

This was also the last time it was fired. 

Developed over a period of three years, the M65 atomic cannon was inspired by the German K5 guns used in World War II. As countries upped the ante and developed their nuclear arsenal, they also looked at ways, including rockets and missiles that could deploy the warheads behind enemy lines. 

The gun named T131 could be transported by two specially designed tractors called T72. Each carriage tractor had a 375 hp (280 kW) engine that could reach a speed of 35 mph (56 km/h). The assembled gun was balanced on a ball and socket joint on top of a footplate, allowing for easy movement and targeting. It could be quickly disassembled and put into a traveling mode in less than 30 minutes. 

On May 25, 1953, the T131 was taken to the Nevada test site and an 11-inch (280-mm) W9 warhead was fired at 8:30 am. The shell exploded 7 miles (11 km) from the firing zone, resulting in a 15 kiloton detonation. The cannon was nicknamed "Atomic Annie."

Apart from the U.S., the Soviet Union and France were also actively engaged in developing nuclear artillery. While France developed the Pluton missile system, the Soviets made the 2S7 Pion, a self-propelled gun for a 203 mm projectile, a towed-gun D20 for a 152 mm projectile as well as S-23 heavy gun for a 180 mm projectile during the Cold War. 

After successfully firing Atomic Annie, it was accidentally sent for overseas deployment under a highly classified mission. This mix-up was noticed at the ten-year anniversary event of the firing, and by the time Atomic Annie was located and recalled, the US Army decided to withdraw the M65 from the battlefront. 

Atomic Annie is now on display at U.S. Military Museum at Fort Sill, Oklahoma, while there are six others on the display at various locations in the country including the National Museum of Nuclear Science and History, New Mexico, Watervliet Arsenal Museum in New York, and Yuma Proving Ground, Arizona.