My 455 - 45ACP conversion measures .097" My 45 Colt conversion left the serial number and has a very light counterbore to allow the thicker base to work. It also allowed the use of 455 ammo. I think that TK Customs made moon clips for shooting 455 in a 45ACP chambered revolver some time ago. I believe there were quite a few conversions done this way, since 45ACP was a very popular round and many saw moon-clips as a handy option. Afterall, the factory used the exact same design for both the British 455 and the Model 1917 45ACP.
