On February 6,1942 the Crosby Company of Buffalo,
New York was given a contract to produce 1,803,258 thirty- round
Thompson box magazines on contract #W-740-ORD-78 for an average
cost of 28 cents each. This was the first of several contract for
Crosby. Crosby ended up producing 5,415,922 thirty-round box
magazines.
Not all was rosy for Crosby. In September of 1942 it was
discovered that 35% of the magazines tested would not fit into the
MI Thompsons. The remaining 65% would fit the MI only with 20
pounds of hand pressure to lock into the gun. It was determined
that due to the Crosby magazines having a more pronounced flare at
the front of the body and the MI's receiver magazine well being
reduced in size, there was an interference fit. The Augusta
Arsenal devised a simple solution and produced some hand operated
tools to reform the feed lips on the magazine. This operation also
required to grind .060 inch from the front of the magazine lips.
Cost of the modification was 6 cents each.
The markings on the Crosby magazine often confuses many
beginning collectors who believe the CCO marks represent Colt's.
Colt did not produce any thirty-round magazines for the Thompson. |