Some Colt and Smiths of yesteryear had up to .457 throats and .450-.451 bores in 45 Colt. Two of my very fine shooting 45's have this "problem".
This is typical in ALL Colt's and S&W's. I don't know what S&W has done as of late but even a brand new Colt will have oversized chamber mouths. Rugers can go in either direction.
The 250gr Keith bullet I recently recovered from ballistic testing showed no wear on the shoulder but the nose flattened and deformed slightly.
