HalfaDouble,
The 109/49 (109.49) on the 9.3x74R is the gauge measurement mark for the bore (not groove or bullet) diameter. This mark dates the gun to before 1912 when the 1911 improvements to the proof law were implemented and after the 1893 implementation of the 1891 proof law. The 8.15x46R seems to have been proofed in Zella Mehilis and the 338 would be the date if proof (Mar 1938) and the 338 would be the ledger number. That these two numbers are so close together is likely just a happenstance. I couls tell better If there was a photo.
Mike
