Thanks very much for your quick reply. I was hoping I could sort out this Ruger No 1 express sight issue for my 450/400. I figured out that Ruger must have used the express rear sight from the M77 Hawkeye, so I bought one and installed it. My rifle shot 12" low at 50 yards with the Hornady 400 grain softpoint factory load.
The M77 Hawkeye has the same express rear sight but the front sight blades are different heights, one for the African model and another for the Alaskan model. I'm thinking that the two heights makes up for the difference in the muzzle velocity difference between the 375 Ruger and the 416 Ruger. The Alaskan M77 Hawkeye offers the 416 Ruger where the African model does not - go figure!
Does your 450/400 shoot to point of aim at 50 yards with the installed Ruger express sights?
Thanks again.
Torpex