Chamber depth is from the rear of the cylinder to the step. There is no rim recess. .45 Colt, Schofield, and 1909 are all too long to fit this cylinder. There was a box with this gun. Stamped in ink was, I believe the number 13. The usual end label was the name ".45 Special". I have heard of other boxes labeled this way but have not personally seen them. S&W must have thought that this cartridge would become regular production.

Ken