7,8mmx57 sporting rifle
I recently picked up a Belgian Mauser sporter that was built pre WW2. Custom gun with claw mounts and raist barrel rib. Very nice vintage rifle. But I am unsure of the caliber. 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?
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?
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I wouldn't trust any marks I've found on a custom gun that was made a long time ago. Have someone slug the bore and cast the chamber. 0 -
European metric rifling dimensions used the bore diameter as the standard measurement. 7.8mm works out to .307+ in our English system. This probably means that your sporter is chambered for the old original .317 diameter bullets rather then the much more common .323 bullets.
To be sure, take Babun's advice have the barrel sluged and a chamber cast made by a qualified gun smith.0 -
X3 for "cast and slug". What price can you put on your safety?
A big painful BOOM!! may await you if you shoot a .323" 8x57mm round in a .318 8x57mm (or smaller) bore.0 -
+1 for bore slugged and a chamber cast. Bubba has had a long time to slip in -06 reamer.
Some of the those claw mounts dove tailed into the front ring spook me.0 -
quote:Originally posted by ta812002
I recently picked up a Belgian Mauser sporter that was built pre WW2. Custom gun with claw mounts and raist barrel rib. Very nice vintage rifle. But I am unsure of the caliber. 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?
To give a little history on this. When, what we call, the 8mm came out the bore diameter was .318" and the bullet was 225 gr. That changed in 1905 when they went to a 154 gr. bullet of a diameter of .323" They are both nominally known as first the 7.92x57J and then the 7.92x57JS. J being the German equivalent of I for Infantry. S being that of Spitzgeschoss or Spitzer.
I have been told, (no proof other than that) that in some instances the earlier .318" bores were called 7.8. Again, no proof. More often I have seen them referred to as 7.9 not 7.92.
So, I'd suggest like the others that you have this slugged. Because, if you translate 7.8mm to inches you come up with about .308". Now, that is not at all common to see. You could see a 7.65 Argentine as a nominal expression of a caliber, but those (.311" nominal) are actually 7.89mm in diameter.
I know it sounds confusing, but it's best to know what you have before attempting to put a round down that tube.0 -
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.0 -
quote:Originally posted by ta812002
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.
The Proof Marks are German. 11.33 is November 1933. 7,8mm is the bore diameter. 57 is the length of the cartridge case in millimeters. "St. M.G. 15gr.", is data reflecting the type and weight of bullet used in the proofing process. In this case a steel jacketed bullet, weighing approximately 235 232 grains.0 -
Still do the cast, pay attention to the NECK diameter.
IMHO the problem with the early versions isn't the barrel diameter, it's the neck. The larger neck diameter (of today's ammo) can't expand to release a larger bullet, causing the pressure problem we've all heard about.
Back in the day, it was common to let the bullet base opturate to fill the bore (easy to do with a open base, heavy weight, round nose bullet).0
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