Just got an unheadstamped .45 ACP that has a very British or Australian look to it. Can anyone ID the round?
GM, brass case, large copper primer, ring primer crimp, purple annulus, knurl at mid case.


Howdy Jon…
Can you post an image? If you need help with that, let me know.



Picture Bump.


Hi Jon - this is an odd one. In the picture, the primer size and the ring around the primer pocket look very much Australian. British rounds with large copper primers are very early (this round is pretty obviously WW2 vintage, in my opinion) and the ones I have all have 200 grain bullets. The Canadian rounds have the copper primer, but not the ring around the primer pocket, and the primer-cup diameter is smaller than the Australian primer, since the Canadian rounds are Boxer-primed, I believe. That said, my Australian .45s have a smooth case cannelure, not knurled as pictured, while my D.I.42 round has a knurled cannelure, although not quite the same knurling as on your round. Somewhat of a mystery. If I were going to err anyway, I would err on the side of this round being Australian, not Canadian or English. I have a Canadian unheadstamped round, but it is c.1962, and has a totally different primer with brass cup, black primer seal, and no case cannelure. There is a companion round to it with headstamp and dated 1962. It would help to know the diameter of the primer in your round - the .38 S&W round shown for comparison (?) is no help - another .45 Auto round with Boxer primer might have been some help in that photo, but that is hard to say. I know of no .45s off-hand that would tell me this could be anything but Australian or Canadian.

By the way, is the bullet GM or GMCS?


I’ll answer your technical questions tonight.
The round to the right is a .44 Russian that I asked about previously. No comparison, I just shot them together to conserve digit space.
I got the .45 round from Werner R., who did say it was Australian.


Jon - no need to send technical information. It is clear your round is Australian. I was wrong about the cannelure on mine be smooth. All of mine are knurled. After I set them down in the collection after looking at the primers, my eye went up to the next row of cartridges in error.


Thanks, John. I did check anyway, and the bullet is GM, with a 6mm primer.


Definietly Aussie Cartridge .450 mark I.
Made specifically for use in TSMGs on issue to Australin Forces, manufacture dates most commonly seen “MG .45 43 & 44” (MG, #2 factory, Footscray).
To save on primers, they used the same copper primer used in the .303 cartridge ( .250"==6,35mm Diameter) and as these cartridges were specifically for use in Thompsons, the “Rifle” primer of the .303 was not too hard.
From 1940-44, Australia relied on shipments of Winchester and Remington “Commercial” headstamped .45 ACP ("White Packets, 50 rounds)
with headstamps WRA .45ACP and Rem-Umc .45ACP, packed in 1000 round Commercial Embossed Wooden crates.

A last run of .45 ACP was done in 1956,(MF 56 .45), same primer dimensions for the RAAF (and RAN) which had inherited the Army TSMGs when the Owen Gun (9mm)became the standard Infantry SMG in 1942-43.

Regards, Doc AV
AV Ballistics.


Is it possible to date (year at least) this unheadstamped round?


Production dates of Aussie .45ACP Known: 1943, 1944 (?1945??) and 1956.
No other production years are known or even suspected, and lots were small,(in comparison to other ammo) given the reduced requirements of the RAAF and RAN, who by late 1943, were the users of the TSMG. ( Army had converted to the 9mm Owen Machine Carbine, and to a lesser extent, the “Austen”).

Regards, Doc AV
AV Ballistics


So would you suspect the unheadstamped round to be pre-headstamp '42-43, ‘43-44 clandestine, or "we don’t need no stinkin’ bunter" 1945?


None of the above…(You Yanks have over-enthusiastic brains)…Just a case which missed being “bunted” with the actual headstamp… which in Aussie cartridge manufacture practice, is a separate operation from either “head forming” or “Primer Pocket bunting”.

Clean cases are also occasionally seen in Aussie .303 cases as well…it is also a sign that the “QA” ladies on the final inspection bench (before packaging) weren’t as attentive as they should have been.

Regards, Doc AV
AV Ballistics