I have a Stevens with the same problem. I tried bedding the base and that fixed the elevation problem, but I need to use 30 MOA shims (10 in the front and 20in the back) in the Burris Sig rings, plus most of the windage in the scope just to get on paper at 100yards. I don't even use that action any more. It bugs me so much that it just sits on my work bench.

Andrew