I WAS EXPECTING AN EARTH-SHATTERING KABOOM: The Time Bobby Kennedy Watched the Smallest Nuclear Explosion Ever. “There was nothing funny about the XM-388, though. The device had an explosive yield the equivalent of 10 to 20 tons of TNT. This was far, far less than the bomb that was dropped on Hiroshima, which had a yield of about 16,000 tons, but Davy Crockett had a different purpose. It was designed to be used against enemy armored forces at bottlenecks such as valleys or mountain passes, where wrecked enemy armor and lingering, lethal radiation would create impassable areas. The XM-388 projectile was launched from the XM-28 recoilless rifle. A small, man-portable recoilless rifle, the XM-28 had a range of just 1.24 miles. An improved launcher, the XM-29, had a range of 2.5 miles. Both were operated by a three-man crew and an a M151 jeep could carry the entire system.”