Some time back there was a thread about the .38-40 and .44-40 cartridges headstamped “REM-UMC .38-40 REM” and “REM-UMC .44-40 REM”. An attempt was made at that time to date them.
I just got some more Remington-UMC catalog pages. Here is the Dealers Price List for January, 1914 showing these loads as “NEW GOODS”. So, we now know the introduction date and that there are 10 different cartridges using this headstamp.