The M-28 and M-29 Nuclear Device Weapon Systems Carrying a M388 Nuclear Projectile
At one time during the Cold War, when the Soviet invasion was on high alert there were a total of 2,100 Davy Crocketts, aimed at East Germany from West Germany. They had no abort feature once committed.
Davy Crocketts are portable nuclear bombs, weighing in at almost 2 kilos about 76 lbs, described by many as Hell on Wheels. It was 31 inches long and 11 inches in diameter. The nuclear loaded projectile was mounted on a rod because it was to big to slip through the barrel and had a range of over a mile, another smaller version had a range of 2.5 miles with the same destruction capabilities.
It was bolted to a jeep like military truck and only took three men to set up and dismantle then get out of the danger range quickly.
The unlucky persons who would be in the 1/4 mile range of such an nuclear explosion, faced possible death. Within 500 ft. radiation would kill you in minutes or hours, 1000 ft. you'd feel tired and nausea then it would pass and you'd feel fine, but just when you feel fine this is when the condition called the "Walking Ghost" gets you, radiation poisoning. You suddenly die. People beyond the 1/4 range you will need medical attention and may survive and those 1/3 of a mile away will have genetic mutations in the future, and have an increased chance of cancer while living.
Weirdly, the timer on the Davy Crockett had a minimum shot distance of 1000 ft. If shot to that distance, the shooters would certainly have died.
Luckily, none except the test models were ever fired and have been decommissioned. Lucky being the key word, because it had no abort feature once committed.
All that would have needed to happen was one trigger happy sergeant, and we wouldn't be here today.
Further Reading: Alien Hand Syndrome and Other Too-Weird-Not-To-Be-True Stories