Dave,
The rear sight is not heavy enough to create much force in recoil, so it is set into the rib. A scope is different, because of the weight. When claw mounts( or swing mounts) are mounted, a section of the rib is cut out and a base(sattel) is fit to the barrels and soldered to them( sometimes glued). The joint is much larger than the joints with the rib it replaced, so it resists the recoil. I have seen one or two guns that had the front plate dovetailed directly into the rib, but since the scopes were "lost" I don't how they would withstand a good bit of shooting. Also, it is a real "trick" to cut the section of rib out, due to the curvature of the barrels. You can only saw it part way, then you have to cut the rest of the way with a very thin capeing chisel. You would have a similar problem with an end mill to cut the rib out. You might have to be satisfied with the Talley base standing a little proud of the rib. If you have or can find a Heym O/U combination gun, take a look at the dovetail for mounting a scope with "slide on" mounts( 1960-70 era). You may have enough room to set a similar section of dovetail in your rib and use one of the Recknagel mounts made for Heym or Brno( same era). From time to time Simpson Ltd has a Brno with a mount for sale at a good price. Of course an O/U is not as "pushed" for room as a SXS (between the barrels), and the dovetail for this idea may have to be higher than the rib to mill the notch for the "lock" to fit into. See what you think. BTW, the 7x57R is one of my favorite cartridges.
Mike
