Entrance to Yuma Proving Ground, Atomic Cannon on right.

Atomic Cannon (In Transition)

Yuma, Arizona

The Yuma Proving Ground, just north of the city on U.S. Highway 95, has offered easy viewing of an Atomic Cannon at the entrance gate since 1963, along with other retired military hardware such as tanks, artillery rockets, and a 200mm howitzer -- weapons actually used in combat, unlike the Atomic Cannon, which never was. The gun sits alone on its carriage, without the dual-end transporter trucks that gave the cannon the ability to "shoot-and-scoot."

If you accept the Cold War concept of the "nuclear battlefield" -- admittedly a big if -- then the idea of an Atomic Cannon makes sense, or at least it did in the 1950s. The Atomic Cannon was promoted as a counterbalance to the massed hordes of Soviet and Chinese mechanized infantry. It would limit nuclear devastation to military targets. Perhaps most important, it would give the U.S. Army -- sidelined by nuclear bombs and submarines -- something to do.

The USA built 20 Atomic Cannons in the 1950s, each with a gun barrel 43 feet long. They were built big to hurl a nuclear shell -- which weighed several hundred pounds -- a tactical distance, up to 20 miles, so that the artillery crew, which took cover in trenches, wouldn't be killed by the blast and radiation. One even fired a live nuclear round at the Nevada Test Site, on May 25, 1953. The shell detonated 500 feet in the air with a 15 kiloton nuclear blast, the same as the bomb that destroyed Hiroshima.

The cannons were all retired from service by 1963, but several survived as outdoor displays at museums and military installations, including this one. But it was removed for restoration in July 2018 (replaced by a non-atomic cannon) and, according to Yuma Proving Ground Museum curator Bill Heidner, there's still no timetable for its return.