I recently picked up a Belgian Mauser sporter that was built pre WW2. Custom gun with set triggers, engraving and raised/matted barrel rib. Very nice vintage rifle. But I am unsure of the caliber. The gun was advertised as being chambered for the Argentine Mauser cartridge, but that round is too short to click into the bolt face, so I knew it was not correct. So I pulled the action and the underside of the barrel is proofed and marked as 7,8mm x 57

Some information I am finding on-line seems to point to this as being the 8mm Mauser cartridge, but nothing conrete on this fact. Would anyone out there be familiar with markings like this from the 1930's or 40's?

Odds are that it's a 8x57 (.318 bore).The .323 bores are mostly marked with 7.9,push a slug through to be sure.

Muzzle measures just over .320

I have found a bit of info on-line about other people having the same markings on drillings, but no confirmation that anyone with these markings is actually putting 8mm Mauser rounds through them.

B.Dudley,
It will take a little more research to say for certain which ammo to use, but 7.8x57 is the normal mark for the German cartridge 8x57I(Infantry). The rifle might accept 8x57IS(Infantry Spitzer). The I cartridge uses a .318" bullet and the IS uses a .323" bullet.The IS would normally be marked 7.9 or 7.92x57, but there was sometimes enough overlap that IS ammo can sometimes be used in an I rifle. Even though you didn't say which action your rifle is built on, American commercial 8mm Mauser ammo is loaded to be safe in such rifles(although a little anemic). If you fire one of these cartridges in your rifle and a .323" bullet will easily go into the neck of the fired case, IS ammo will likely be useable.I'm sure more information can be given if you provide photos,including clear photos of the Proof marks(likely found on the bottom of the barrel).
Mike

The rifle is built on a Belgian Mauser action. I will try to get a good picture of the proof markings. If not, I will list in detail all the markings here.

Here is a photo of the proof marks on the bottom of the barrels.



To clarify, here is what it all reads.

Crown over B, Crown over G
Crown over U
7,8mm
57
1133
15056

Then perpendicular to the above:

Crown over N
St.M.G.
15gr.

Again, the gun is built from a Belgian Mauser model 1889

The muzzle measures just over .320 across the valleys and .310 across the ridges.

Proofed in the final state in November 1933 for a 15 gram bullet. Axel has a dissertation on the 8x57IR and this may be a portion of it:

"Apparently the changeover was completed 1926. Jon Speed's book "Original Oberndorf Sporting Rifles", page 274, shows a table of cartridge dimensions agreed upon July 23, 1926 by the German arms and ammo manufacturers association. It shows new//old designations: 8x57IR // M88/8 mit Rand or M88B, 8x57I // M88N, 8x51 // M88/8 kurz or H, 8x57IS // M88/8S.
The German M1888 cartridge was loaded with a .318" 14.7gramm = 227grs (roughly 15gramm)round nose bullet. This was the standard/only hunting load up to WW1. The military S cartridge used a .323" 10g = 154gr pointed bullet that never became popular as a sporting load. In WW1 the German army changed to the sS = heavy pointed bullet for machine gun use, bullet weight 12,7g =196gr. This became the standard weight for both the I and S bores close to WW2. Up until after WW2 the I = .318" bullet was regarded as the sporting type, while the S-bore was the "military" one, used on Sporting rifles mostly for the "Magnum" loads to relieve pressures. Only the 1940 proof law introduced min-max dimensions and the strict differentiating between I and S bores. So take any rifle proofed for a 15g bullet to be an I bore. "

Is there a different twist in the 8x57IR & 8x57IRS?

Kind Regards,

Raimey
rse

I would like to know about the twist rate, although the 196gr. Sellier&Belloit ammo groups exceedingly well in mine, and it is proofed for the 15 gramm bullet. I am less familiar with the rimless ammunition availability. The rimmed version is a cinch to find--picked up two boxes from Graffs a month ago for $19.95 a box of 20 plus free shipping! Don't know what the price will be on the rimless. Good luck. Sounds like an attractive rifle...maybe some additional photos? Steve

B.Dudley,
It wasn't mentioned above,but your rifle was proofed in Germany,not in Belgium.Based on this,and your description, your rifle was likely to have been built in Germany,as well.Rifles like this are often made on M88 actions, and by 1933,surplus M98 actions were readily avaliable.How sure are you that yours is an 89 Belgian action. American made 8mm Mauser ammo(Rem.,etc.)is perfectly useable in your rifle.
Mike

I will put up pics of the gun later today. It is an earlier style small ring Mauser with 2 locking lugs and screw retained safety. So based on the proof marks it is a .318 or a .323? Or we can't tell for sure? Like I said, the muzzle diameter seems to suggest .323 diameter.
I was kind if thinking that 1933 was the proof year and I would have thought by that time that the .318 bullet was phased out.

Based on the barrel markings, it was made to use .318 bullets.

Here are. Few photos of the gun in question.

To find dia.of barrel grooves,"slug" the barrel, or make chamber cast that extends into barrel.
Mike

Looks like the Gewehr 88/97 Mauser had a 1 turn in 240mm(right hand), Mauser 1896 had a 1 turn in 165mm and the Gewehr 98 S-Munition had a 1 turn in 240mm. I'll have to search for the other.

Kind Regards,

Raimey
rse

The 8x57 mauser ammunition available from many American and Continental suppliers will be .323 dia., NOT the .318 which you are looking for!

Ok. So we are 8mm mauser as i thought. Sounds like I need to slug the barrel to confirm the diameter will do.

steve white,
I have a "pile" of Rem.8mm/170gr bullets for their 8mm Mauser ammo.These bullets measure .3215",which was one of the things they did to hold the pressure down,together with "light"loads.
B.Dudley
If Rem.8mm Mauser won't chamber,call Buffalo Arms.They have a selection of .318 bullets and sell custom loaded ammo.They may have 8x57I( they may list it as 8x57J)ammo for sale.BTW, if they don't show it on their website,call anyway.
Mike

Thanks Der Ami !

this is the real deal 7.8mm x 57[img]https://photos.app.goo.gl/y7A17zsA9E1K5C5u8[/img]

[img]https://photos.app.goo.gl/y7A17zsA9E1K5C5u8[/img]

Im a little late

The action does not have the Mauser full length extractor on the right side of the bolt.
The Belgian 89, Argentine 91 and Turkish 1890 are 3 Mauser variants that use the small short spring loaded 'claw' set flush with the bolt at the head.
An advantage of that style is that you can very easily close the bolt on a rd dropped into the chamber. But controlled feeding is not a sure thing as with the standard MAuser extractor.

The 1889 Belgian and the 1891 Argentine are the same rifle for the sake of conversation, the Belgian variant uses a sheet metal heat shield around the bbl. They both use a 5rd straight line feed magazine, the magazine extending below the stock line in front of the trigger guard.
The Belgian 1889 was mfg by FN and a very few by Hopkins & Allen in Ct/USA. The Argentine 91 made in Germany and in Argentina under license. The Turk was German made.


Another feature I note is the long sweeping contoured arm off of the bolt release that fits the contour of the rear ring on the left side.
I don't recall any of these using that feature, though they may have.
The later Turk Model 1903 used it. But that rifle is a clone of the Spanish 1893 Model and used a flush mounted 5rd staggered mag and standard Mauser claw extractor.

Someone had to have converted the 89/91 type action from it's single stack feed system to the 5rd staggered flush magazine w/floor plate

The 89, 91 and even the Turk 1890 rifles were all orig in 7.65x53 Mauser cart.
That got to be known as the 'Argentine MAuser rd' when those rifles were all over the surplus market.
Early reloading dies and some ammo was marked 7.65 Belgian & Argentine Mauser however. Some people still recall it by that name.

re: .318 dia 8mm bullets. I've used .32 Winchester Special bullets in my reloads for the round. They measure at .320 usually and are very thin jacketed. I've never had any issues using them but I always use starting loads to kill paper targets.
I use standard 8mm loading dies, but I don't use the Expander button.I just resize them and seat the bullet in the case at that sized dia. The small(er) dia neck seems to work out fine.
You have to de-prime separately of course but it's not a big deal.
I shoot them in M88 sporters.

Nice rifle!!

Discus
420,
The cartridges in the link you provided are most assuredly not any variant of the 7.8/7.9/ 7.92/8mm x57 cartridge. They appear to be handloaded 9.3x72R cartridges using Norma cases and cast bullets of unknown weight and unknown powder charge.
Mike

They don't look quite right for 8x57R (360) cartridges (most commonly made from 9.3x72 brass) which was found often in drillings.

HalfaDouble,
I handload for 8x57IR, IRS, 8x57R (360), and 8x72R. The cartridges are not necked as the 8x57R (360) would be (9.3x72R cases are sometimes used for 8x57R (360) however). They would more likely be 8x72R loaded in 9.3x72R cases, than 8x57R (360), but they don't seem to have enough taper to have been sized to 8mm. On reflection, the cast bullets might be 9mm Makarov bullets. They are the correct diameter but at 95 grains, they are too light. I have tried the Makarov bullet in 9.3x72R plinking loads, but the accuracy was not satisfactory. I believe the inaccuracy is because they are short enough to tip before entering the rifling.
Mike