I have a Ruger New Model Blackhawk that I broke the rear sight blade. I searched the internet as I was having trouble installing the blade as it has a little nipple. The only advice I could find is that the rear sight assembly should have a half-moon cut-out. The instructions were to compress the spring, slip the sight blade in and then install the screw. The only problem is my gun does not have a half-mood cut-out for the sight blade to slide down in to. I thought of filing the nipple off of the blade and thought better of it as it would have nothing to hold it in. I know I can buy the entire sight assembly for $15 bucks, but 15 is 15 and I would rather spend 3 on the blade. Can anyone give me a tip on how to conquer this. Thanks in advance for all help.