I recently acquired a steyr 1912 rifle, with no information on it. The barrel is stamped Stephen Grant and Sons along the top and some proof marks as well as sr#. Also on the barrel is stamped 6.5 ?/m. The stamp is upside down and I can not Rees what is in place of the question mark, possibly a T. I was told the it could be a 6.5x54 MS. It does seem that it has 2 sr#'s and all parts are stamped with at least 1 of not both. The rifle came out.of a large estate collection as shown. If anyone can give me any information on it it would be greatly appreciated. I would like to find the caliber, so I was thinking the only accurate way would be a chamber casting, but am not sure? Pictures are posted on image gallery .

steyr images

Unless is has been rechambered, it is almost certainly a 6.5x54ms. Making a chamber cast is always a good idea when when you're not sure, better safe than sorry.

Your rifle might have started life as a Greek military rifle, as I believe that Steyr made them for Greece.