I am working with a 450/400 and attempting to install the 275 (7x57) Rigby express rear sight. This is part D07725HM to replace D77.
I loosened the locking screw and drove the dovetailed D77 sight out. That is right to left. Then when I go to slide the D07725HM express sight and it just slides in one end and out the other. I can even see daylight around the express sight. I can drive the D77 back if I want too. Left to right, no problem.
The first question is has anyone removed the adjustable sight and installed the proper express sight on their 257 Rigby No1? if you did that how did it work out? Exactly how? Did you get instructions?
One key detail around the sight is a vertical screw and what looks like a tapered collar that locks the sight into the dovetail. I think what I need is a new collar. I dont see part numbers for the little screw or collar on the parts diagram. That collar is stuck in there good. How is that removed? I am guessing I need to remove the rib and drive it out from the back side. That scares me. I bet those 4 rib screws are very tight and maybe locktited in place.
I probably will call Ruger tomorrow. it would be a lot better to know as much as possible. Part names,etc. I refereed to the Rigby No1 when I ordered the sight.
Link to parts list:
http://ruger-docs.s3.amazonaws.com/_manuals/no1.pdf
