This 2nd Model has very good crisp and tight mechanical function. The bore is very good bright and shiny but does have traces of corrosion. The serial number is 5508 with US on the butt and way made in 1877. 45 S&W could be fired in a Colt 45 single action but not the other way around. It retains about 65-70% original nickel finish and nickel finish was very scarce. The grip has a toe chip and there is an Inspectors Cartouche is on it. This is a very good original Indian Wars era US Military revolver.