Miller,I did say "to British proof size" were there is a maximum and minimum ,there is also a tolereance on the length. I can send them to you. You and I are not going to agree on this subject and I dont want to get into a protracted argument that is neither helpful or relevant to the original question. Homless joe says"He is more concerned with the chamber length than the proof status" , well it depends on what you want to shoot out of it and how much you value your fingers.