Terry, I agree with your interpretation of the written rules pertaining to chamber length. However because the proof test charges [powder and shot] are higher for 2 3/4 chambers than for 2 1/2; it will be appreciated that the proof marks of the day failed to differentiate between the applicable chamber lengths.This could well be the reason for the supplemental chamber length marking. Following the introduction of Nitro powders the rules of proof were ammended, such that 2 1/2 chambered guns were marked 1 1/8 ozs max, and 2 3/4 chambered guns were marked 1 1/4 ozs max. Perhaps contributors active in the English gun trade could offer advice on this issue?

Last edited by Roy Hebbes; 07/26/09 02:11 PM.
Roy Hebbes