I have a .38-55 cartridge that I need some info on. It has a copro-nickle soft point bullet, the hs has U.M.C. at 12:00, S at 9:00, H at 3:00, 38-55 at 6:00 and has a small rifle primer with a U on it. What’s with the small primer? Any info would be greatly appreciated.
Thanks, Frogbert

The S and H mean that the case is of “solid head” construction, as opposed to the earlier “folded head” construction. UMC is Union Metallic Cartridge Company. The case dates from the early days of smokeless powder, before US-made cases had standardized primer sizes. The U on the primer indicate that the primer was made by UMC. My guess is that the load dates from 1900 to 1910.

I would suggest that the cartridge in question falls into the Marlin category. If I remember correctly, John Marlin specified .175" diameter primers for cartridges intended for use in Marlin rifles. There were ads put out by Marlin back in the day stating that the only ammunition that should be used in Marlin rifles was that made by UMC, as that made by WRACo was not suitable.


I agree with Randy. Also, a letter on a primer usually indicated a load other than black powder, or, an improved primer. This was common during the ‘transition period’ when smokeless and semi-smokeless were coming into play. A case cannelure is also an indication of a smokeless load.