Nice looking gun

Chammbers are smooth yes, but, I can see the step from case size to throat size about 3/8" from the barrel end of cylinder. The cylinder retains the serial number and has no shallow recesses at the chamber, so if it was originally a 455 it would have needed about .02 taken off the face of the recoil shield because the colt has a thicker rim. (I think the recoil shield does look shaved) Of course the chambers are reamed deeper on a 45 colt than on a 455. If they were reamed deeper after production it would be difficult to see if the smith did good work.

Some S&W 45 colts were made for the Canadian RCMP. I would love to have one.