REM-UMC headstamp change to R-P


Would anyone know approx when that happened?

Thank you,



REM-UMC : Original small thin letters = 1912

REM-UMC : Taller letters = 1920 +/-

REM-UMC : Wider letters = 1930 +/-

R-P = 1960

These are approximate dates because some changes may have taken place later, depending on the particular cartridge and how much the demand was for it and when the bunters wore out. The exact amount of the change in sizes could depend on the size of the case head.

Got a particular cartridge in mind? There was an old thread on this where I showed some examples. Not sure we could find it now and I’m sure the photos are gone, regardless.



Ray–While your information is correct, the “R-P” headstamp can be further refined. The “-” was changed 4 times. This info applies to the headstamp on .222 Rem., but the dates are ballpark for other calibers.The original was 0.1742 (4-14-60) which shortly was changed to 0.1739. Later it became 0.040 which on 12-30-70 was revised to 0.015. With the move to Lonoke, Arkansas from Bridgeport, Conn. about 1985, the headstamp was changed to a “.”.


Ray, Ron,
Many thanks for the information. I know that the dates can vary a bit depending on the cartridge but that gives me an approximate date range.
Ron, I remember seeing the the dash variances as the years progressed. Thank you for that information.

Ray, my memory isn’t that good but were you the one that wrote an article for the Handloader magazine back in the 70’s about heavy bullets in the .45 Colt?

Thank you again,



Wow! You can remember that far back? Yes it was me. That was before the 45 Magnum craze took over. My loads back then were pretty tame compared to what we see today.

I also wrote for True West, Frontier Times, Man At Arms, and a couple of others that even I can’t remember now.




Neat! The reason I remember that is because I used your information as a reference when I experimented with heavier 350 and 400 gr. cast bullets in my Ruger Blackhawk. My reason for doing so was to find a recipe that would be 100% positive on the IHMSA 200 meter steel ram, which at the time was giving the .44 Magnum boys fits with which they were finding only about 70% positive on the full footed ram.

The 350 @ 1,100 f.p.s. proved to be 100% positive. I enjoyed telling the .44 Magnum boys that I wasn’t having any trouble and I was using a 100+ year old cartridge… Ha!

J.D. Jones was present at those early IHMSA matches and became interested in the heavy bullet .45 Colt recipies. I gave him some bullets to try and he was impressed with them. Eventually he came out with some heavy cast bullet designs for the .44 Magnum.

Ray, a belated thank you for your guidance.



I lived in Alaska at the time and the heavy loads were supposed to be for bear protection. But I never was comfortable carrying a pistol for bears even though I was a pretty good shot. I preferred a rifle or short shotgun with slugs. Guys have been eaten trying to stop a bear with a handgun. ;(

My son still lives in Alaska and still has the S&W revolver that was in the article. On cold nights my hand still hurts from shooting that thing 40 or 50 shots while chronographing. ;)