Davy Crockett was a dirty bomb. No Nuke explosion.
Critical mass or implosion devises are not small.
Wikipedia and other sources contain statements such as, “The M-388 round used a version of the Mk-54 warhead, a very small sub-kiloton fission device. The Mk-54 weighed about 51 lb (23 kg), with a yield equivalent to somewhere between 10 and 20 tons of TNT—very close to the minimum practical size and yield for a fission warhead.”
I see a video of text firing the device and it looks like a significant explosion to me.
I see a picture of a man holding the warhead with a yield four times as great as the largest conventional bomb produced by the Allies in the Second World War.