Not sure if this will help but I had a 77/50 Black Powder and that particular sight is used on a number of different rifles. Anyway, the point I want to make is I was missing one of the tiny screws that holds the elevation adjustment plate in place on the rear sight. I contacted Ruger Customer Service and asked if I could purchase one of these tiny screws. They sent me an entire rear sight assembly - brand new - no charge! If nothing else they could certainly tell you what sight you need. Might be worth a try!