My favorite Roscoe is a S&W m12. It has gone by many names, from Revolver Lightweight .38 m13, to the Military and Police Airweight , and finally to the model 12 when S&W went to model numbers. As near as I can determine there are four “dash numbers”, or engineering changes. Leaving out the more esoteric parts of its history (aluminum cylinder models, specially loaded low powered loadings of the cartridge by the U.S. military), the main changes that are of importance to the user, are that the 12 to 12-3 use a narrower grip-frame, so standard Smith K frame grips wont fit properly, unless it is a “-4”. Few grip makers make “thin frame grips anymore, as the last
M12 left the factory sometime in the mid 80’s.
