Here's the deal:

I'm trying to get a Model 70 .458 to work with a Williams receiver sight (WGRS, the slick little one that sits on top of the rear receiver bridge).

With the sight in the middle of its' range of vertical adjustment, the rifle shoots about 7.5 inches low at 50 yards with full house 510 grain factory loads, although it groups quite well. With a 25.5 inch sight radius, I think this is telling me that I need to raise the rear or lower the front about 0.104 inches. On something this heavy I don't want to run the sight to the end of its travel and have half of it hanging out in space off of the dovetail.

There isn't room to use a different front sight that much lower; the best solution I can think of is some kind of shim under the WGRS to raise the rear by 0.10", and use longer screws of course.

Are there any other, better solutions?

What would be the best shim material?

Thanks in advance for your advice.

Les

LRH270,
You're right on the calculation for your required shim thickness, and I would recommend milling & drilling a mild steel block, then bluing it to match the exposed edges with the action.
Say again why the front sight or base can't be lowered?
Hotshot

Well, I guess a lower front base is a possibility but right now the front bead centers in the hood, which is pretty slick with a rear aperture (just line up the concentric rings).

Try asking Williams first.
Good luck!