the USS New Jersey battle ship.

I did not read all of DC 340's post but what I gleaned. From the article, was.... They were firing a 2700lb shell with powder specifically for a 1900 lb shell, and marked "do not use with 2700 lb shell"
Also, apparently the rammer (for the shell and powder bags) was over extended. During simulated tests, explosions happened.
Also, all of the 16"turrets were manned by inexperienced unqualified sailors, with turret 2 being the best qualified of the three. Hardly surprising, since the guys that knew what they were doing in that turret probably retired or were mustered out 40 years earlier.