Mystery 7.8 x 50SR Cartridge

At a local gunshow this past weekend I got to examine this round.

Projectile: 7.83mm
CL: 50.3mm
OL: 71.92mm
Rim diameter: 11.84mm
Base diamter: 11.61mm
Shoulder diameter: 10.65mm
Neck diameter: 8.61mm
Rim to head: 2.81mm
Rim to shoulder: 40.3mm

I have no idea what this round is (assuming that it is legitmate) or what it is based on. It looks not unlike a 6.5 x 50SR Japanese, but the extractor groove is not as big (tall). The projectile has a CN jacket.

The primer is brass and there is no headstamp.

Any guesses?


No sign of a headstamp at all, or headstamp was removed?

Just a guess, but how about Chinese?


Thanks Tony. Why would you suggest Chinese?

Jon - there is no headstamp. Was one removed, I have no idea. The case looks like it has been cleaned and polished so I suppose it’s possible that any remnants have been erased.

The owner is considering pulling the projectile. If he does, I will post the results.


The only reason I thought possibly Chinese was because in the war lord period around the end of the 19th Century there were one or two odd rounds developed in China, but it was really just a guess.


My first thought was that it was a reloader’s attempt to make some shootable 7.35 Terni ammunition.

Dimensions are close to those of the 7.35 mm terni and that cartridge should work in a carcano rifle except for the bullet diameter. A carcano with worn rifling that has been rebored to .308" ?

Could we see the case head?

Sorry I don’t have a better picture of the base.


I think that they modified a 6,5 arisaka case to form a 7.35 Terni .3082 diam bullet

Very few cartridges have similar head diameter. carcano/ terni and 6.5 mannlicher Schoenauer

Pivi: Your points are well taken, but I don’t see how this thing could be made to feed through a Carcano action with that large rim, assuming it was intended to be used in that arm. Also the apparently large diameter primer makes me wonder if a 6.5 m/m Arisaka was the base cartridge. Jack