gjw,
In my opinion the cardinal sin in so far as British doubles are concerned is to increase the chamber length from 2 1/2 to 2 3/4,[Rendering the gun out of proof] without resubmitting the gun for re; proof!
It continues to amaze me that some individuals think that they are improving the safety of a gun by removing metal from the barrel chambers so that they can insert a 2 3/4 shell. Which of course has the potential to create pressures much higher than that generated by the original 2 1/2 proof test.
In this day and age,it is odd that concerns that existed almost 100 years ago in relation to shell versus chamber length are still influencing owners to make unwise decisions.


Roy Hebbes