I have a 10 bore Joseph Lang BL with 32" barrels made sometime in the 1920's. It was made as a 2 7/8", but I had it changed to 3 1/4". The work was done by a chap in the west of England (forgot his name) and he also made me 3 1/4- 1 3/4oz shells for the gun. I addition I got some brass shells too. They all worked fine. With no. 3 (GB) pellets, it is a very good goose gun with a nice balance. As I understood it, he had done that operation with many 10 bores.