Some of those old Weaver rings are stamped and they can really ding your scope tube when you tighten the screws (ask me how I know). If you look on the inside of the rings, you might see a couple of small bumps on either side of the little flat spot for the screw head. I had one set of Weaver rings where it was really noticeable. I had to very carefully file off those bumps. No more scope dings after that little operation.