Chambers....I made a C/S casting of a JP&S 12bX 2 inch some time ago, built in the 1920s. The end of the chamber actually had a"Step" at the point where the F/C led into the 'bore'.the Forcing/C was practically Non existent. At a later date I had a J.Lang 2" in the W/Shop that my chamber gauge showed had been lengthened to 2.3'4"+!!No Re-Proof by any Proof-House!!No Bulges in either barrel either!!! CC.