Mike,

The easiest ways to add flexibility to your choice of scopes, keep the front ring off the objective lens body (when it's larger than the tube), and retain the position of the existing "claw" bases is to have a set of offset (fore and aft) claw rings or a "rail" mounted to your current bases. Both aren't necessarily the cleanest looking ways of mounting a scope but the later gives you a great deal of flexibility, allowing you to position your scope rings anywhere, within reason, along the length of the rail. To 450_366's point, the rear of the mount system has to be lifted out of the rear base (quite a ways actually) in order for the front claws to be pulled out of the front base. One has to be sure that all this can be done without the front of the mount or the scope hitting the top rib or in some cases the rear iron sight. A rail mount works out nice when the existing front base is substantially forward of the rear base and you wish to mount a shorter and often lower power scope to your gun. A rail mount with dovetail grooves or, I cringe saying this, a Pecatinny rail system provides the greatest amount of flexibility. The base configuration in example below is similar to that of the subject gun on Holts and should give you an idea of the sort of thing that can be done.

Buchseman