The M65 280 m.m. atomic cannon weighed 42,500 lbs. and measured 42 feet in length. One of only three in existence, the other two are located at Ft. Sill, Oklahoma and the U.S. Army Ordinance Center in Aberdeen, Maryland. It was placed in service November 17, 1952 and deactivated August 1963. Two 375 hp engines transported the cannon at 35 m.p.h. It could fire a projectile 11 inches in diameter for more than 20 miles, but the cannon was never fired.