In 1944, the Port Chicago disaster killed hundreds of Americans in a single blast. On the night of 17th July 1944, two transport vessels were suddenly engulfed in a gigantic explosion. Officially, the world's first atomic test explosion occurred on 16th July 1945 at Alamogordo, New Mexico; but the Port Chicago blast may well have been the world's first atomic detonation, whether accidental or not.
If you can believe it, the "U.S." Navy dropped a NEVER-TESTED gun-assembly atomic bomb on Hiroshima on August 6, 1945. Officially, the only nuclear device they tested was the implosion type bomb that was dropped on Nagasaki on August 9, 1945. If you believe that, then you can believe that the earth is rotating . . . or Walt Disney landed men on the moon!!
The first atomic bomb dropped on Japan was the NEVER TESTED gun-assembly device!!
The inventor of the gun-assembly device was Navy Captain William "Deak" Parsons.
So confident was he of his invention that he felt that no test was necessary of the most important part of the bomb: the nuclear chain reaction.