Okay, another puzzle found in the writings of the officer...

On July 26, 1943, while aboard the ROBERT J. COLLIER, he mentions that the "old .50 cal. ammunition boxes amidship" were filled with 20mm ammunition. I find this remark interesting in that this was the COLLIER's first voyage, having been launched June 28.

The COLLIER was not armed with any .50 cal. machine guns so why the reference to the "old" ammo boxes? Was the ship constructed using somewhat outdated plans that incorporated ammo boxes for the .50s? It is my understanding that by this date, the .50s had been replaced by the more powerful 20mms.