Very glad to be a new forum member, and I have enjoyed reading all the posts in the Mannlicher sub-forum

I have a question about the proper cartridge for a Steyr Mannlicher based on the 1903 model, built in 1930, which I believe is what they called the 'High velocity Rifle' with the longer action to handle cartridges such as 30-06 and 8mmx57. It has what I believe to be a contemporary scope in a wonderful detachable claw mount. The scope is marked Hentzoldt - Wetzlar Dialytan 4x.

I bought it used at a gun show many years ago, bearing a tag labeled as 8mmx57, but have fired it very seldom as I was concerned about the actual caliber once I started doing research about the multitude of calibers these rifles were offered in.

I had a chamber casting done by the only gunsmith I could find to do one in the part of the United States I lived in at the time, and he said it might be 8x57, but no more than that. I have not had the barrel slugged.

Based on that limited information I shot 4 or 5 rounds of some commercial 8x57 Mauser ammunition which I understand is loaded very mildly to deal with the .318 vs .323 bore differences.

To make a long story shorter, I recently screwed up my courage and removed the action from the stock and found the following markings on the bottom of the breech (described row by row):

Crowned B Crowned C

Crowned U

7,8 mm

56 1/2

6/30

3251 A sideways T in a circle

{Then running vertically}

+
0
5
*

8
0 2

I am assuming that this is chambered for a 7.8 mm bullet in a 56 1/2 mm case and was built in June 1930, serial number 3251.

I certainly have not been able to find such a cartridge based on my feeble Google skills.

Please see (poor) photos:

Breech:

Rifle:

amd

Album here:

http://imgur.com/a/Nzajb

Any and all help very welcome, specifically in determining if this is chambered in a caliber I can find cartridges for or reload. Ideally I would like someone to tell me that I can shoot commercial hunting 8x57 Mauser loads such as the Remington Express Ammunition 8x57mm JS Mauser (8mm Mauser) 170 Grain Core-Lokt Soft Point, which at least spools into the magazine, unlike spitzer rounds.

I remain, a puzzled, hopelessly in love, proud owner,

Tom Porter