8mm WHAT?

These rounds all have nominal 8mm projectiles [measured at the cartridge neck] but, the two in the middle…?

On the left, standard military round measures: 8.18 x 57 mm [19 ? 64, 3-point primer crimp, steel case, steel projectile]

The second from left measures: 7.83 x 53.84 [???, 3-point primer crimp, brass case, steel projectile] appx 43.85 mm from base to beginning of shoulder

The second from right measures: 7.92 x 53.56 [ORBEA 1947, brass case, non-steel projectile] appx 45.06 mm from base to beginning of shoulder

On the right, standard commercial round measures: 8.19 x 56.72 mm [R - P 8m/mMAUS]

Keep in mind that mostly the caliber “name” is smaller than the bullet diameter (cal. .30 while diam is .308 for example). So we have no 8 mm here.
The 2nd looks to be a 7.5 x 54 French Mle 1929C (7.5 not withstanding, bullet diameter is the same as 7.62 NATO, for example: 7.8 mm). Note the larger base diameter.
The 3rd looks like a 7.65 x 53 Argentine (CIP name; called 7.65 x 54 in Argentina; designed by Mauser and first adopted in Belgium 1889). Bullet diameter is the same as used in Russia for their 7.62 mm calibers or .303 British: 7.9 mm diameter.

To add to JPeelen answer:

For the 7.5 x 54mm French MAS cartridge-

For the 7.65 x 53mm Mauser cartridge, ORBEA = Cartucheria Orbea Argentina, 1947

Cartridge 1: 7.9x57 Czech made 1949 -50s Military also for Export
Cartridge 2: 7.5x54 French M24/29, made Defence Industries Damascus, Syria 1950s)
Cartridge 3: 7.65x53 Argentine, by Cartuceria Orbea Argentina.
Cartridge 4: " 8mm" Remington made commercial 7.9x57 for sporting market…may be reload?

Doc AV

Cartridge 1: 7,9×57 Bulgarian made, factory code 10 in Kasanluk, dash for single primer hole, triangle for copper plated steel case, 64 for production year.

Hans

Yes, my mistake, 1 is Bulgaria…could not get a clear look, just the triangle indicated Czech 1949-50s.

Doc AV

The Remington Peters I just included for size comparison on the other end, it is a factory load, I have a couple boxes for my backup to my backup rifle to my backup handgun for deer season…

Thanks, I was thinking the 7.5 was Egyptian, but the writing did not quite ‘look’ right, and I never would have guessed 7.5 French!
I should have recognized the 7.65 Argentine: I have several boxes of once fired Norma brass,
(and I might still have one box of loaded?), but no rifle to shoot them in.
Both rounds are now properly marked, thanks to all!
And thanks for the ID on the 8mm- I have a bunch that I need to go through!

The 7.65 x 54 cartridges headstamped “ORBEA” were made by Cartuchería Orbea Argentina S.A. in the form of primed cases and bullets, but loading was done at F.M.M.A.P. Borghi and San Francisco. Known dates are 1945, 1946, 1947, 1948 and 1949.

Regards,

Fede