Is it a Collath hammer drilling possibly with a proprietary chambering of 7.3X57R Teschner, or have you done a chamber cast? If it's a pre-1910, more than likely it was a black powder cartridge with a lead bullet without a jacket, unless stamped so. I think Mauser was driving the 7x57R train in 1892 and sometime thereabouts the Brits had the 0.275 Rigby as the rimless version.

I'd say the 248 is a proofhouse number.

Kind Regards,

Raimey
rse

Last edited by ellenbr; 12/17/08 09:55 AM.