Just saw your 'op' on this.

I have used an RCBS two die set for the M1910 with excellent results. It was labeled '9.5X57 Mauser' back in nineteen eighty - something.

New, properly sized, brass marked 9.5X57, 9X56, 8X56, 6.5X54 is available from Quality Cartridge (Qual-Cart) from time to time.