Also called the Model M. The 1903 was in 32 acp and in .380 it was called the 1908 for the year it came out in that round. Colt made about 550,000 of the 32 Acp and about 135,000 of the .380 with those during WWII going to the government and a lot of these being issued to General officers of WWII in both calibers. If you have one with the paperwork linking it to a general Officer it is really a find. General Patton wore his .32 quite often late in the War.Charlie said:I think they were chambered in .32 ACP or .380, but not positive. They were a smaller caliber from most of the self defense pistols commonly used today. Someone else may chime in with more accurate information.