I know this isn't what you want to hear, but quite often original guns are "off" a little, too. (Although I'm often amazed at how close point of aim/point of impact is!) You have to remember they were sighted for "minute of man". If you're shooting your SAA at a "hostile"'s chest at fifteen yards in 1876 (or now, for that matter), you really don't care if it hit three inches to the right. He's still dead. Three inches at fifty feet from a carbine, however, DOES seem excessive. Good luck with it!