rctsat,
You mentioned rough chamber and barrel measurements,but didn't provide any. 9.5x47R was also a popular "Schutzen" cartridge in earlier times and may be found with the caliber marked as 9.3 or the gage equivalent( bore,not bullet dia.).The head dia. of this cartridge would be something over 1/2", and the 8.15x46R(mentioned by xausa) would have a head dia. less than1/2"( around .425-.427").The best way to determine the caliber is to make a chambercast.
Mike