Here arethe shotgun prooftables for a start. The left page, "Vorderlader" is for muzzleloaders, the right one, "Hinterlader", for breechloaders. On the left you see the Kalibernummer = gauge number as stamped on the barrels. The next column is the bore diameter in mm. Germans use a comma instead of the decimal. Then comes the prescribed charge, gram blackpowder and gramm shot, for the first or preliminary proof, the load for the second or final proof and finally the intended srandard service load.
This is the table for barrels intended for bullets, rifled or not. Again, the gauge number is followed by the diameter in mm, the powder and bullet weight for the 1st,2nd and sevice load. These gauge numbers on rifle barrels cause a lot of confusion now. They stand for the bore or laand diameter of a rifled barrel, not the groove or bullet one. Gauge numbers were used by the Zella-Mehlis proofhouse up to 1910, Suhl to 1912. Mauser, Oberndorf proofhouse, even stamped them on some barrels post-WW1. All Mauser .22 barrels up to 1945 are stamped with the gauge number "459".
