45 aficionados

The Journal n0 532 ls listing under the 45 a round with the stamp US GOVT M1907
NARROW EXTRACTOR GROVE(UMC.45 A.C.P.(headstamp) at 60$
What I like to know is how do I reconnice a MOD 1907 round.The rub here is
that I have this round it must even be one of the older types because it has the
impressed U in the primer.I measured this round front right and center and was
not able to establish any difference between a common round and the one
listed in the Journal advise would be nice.

Sherryl - Firstly, all UMC .45 Auto cartridges have the impressed “U” on the primer. That primer marking continued into use even after the joining of the two companies, UMC and Remington, c.1911, when the headstamp became REM-UMC .45 A.C.P. Therefore, that feature is no guide to whether the cartridge is an earlier or later one.

However, the narrow extractor groove, of which there are two forms of the extractor groove and bevel, differing in the diameter of the cartridge head at the bottom of the extractor groove, and the early one appears on two different cartridges, one with no headstamp (but still the “U” primer) and one with headstamp, the former being incredibly rare. In mentioning the two forms, I mean two forums of the NARROW extractor groove.

Counting the unheadstamped cartridge, there are at least 8 forms of ordinary ball rounds with the UMC headstamp. I also have two dummy rounds, not included in that count, and there may be other rounds not yet known; perhaps other forms of dummies and possibly a proof round.

The story is too long to tell here. See the following entries in IAA Journals:

IAA Journal Issue 487, Sep./Oct. 2012, “Sorting Out the UMC .45 A.C.P. Rounds,” Woodin Laboratory, compiled by John Moss, pages 18-21.

IAA Journal Issue 489, Jan./Feb. 2013, “Letters to the Editor,” ref: “Sorting out the UMC .45 A.C.P. Rounds.” from John Moss, page 13. (Additional information and errata).

John Moss


Thank you for your very informative reply,I will definetely dig our those Journal issues
now i never knew there were un head stamped rounds.Yes it has been a habit of mine
to view stamped primers more early than the rest of the lot,however as stated totally
unsubstanciated…Thank you again

I didn’t know about the unheadstamped ones, either, Sherryl. I found out after I published the original article, hence the addition in the later one. I missed it when I did some research with Bill W. on this. I did not spot it in his collection, and he didn’t mention it - no reason why he should of since I was making notes from his collection. The pictures are of those in my own collection. There may be other very minor variants, but none that I am aware of at this time.

John Moss

thanks for the adicional info,these 45 really got under my skin,however what I have
is relatively small but I am only interested in the old ones they can really be fascinating
I have some for trade,but as you know these days that has become a wild dream thanks