#1). You can often find a substitute bolt (expensive) that headspaces and have the handle bent... You would also need to drill and tap holes for scope mounts which would impair your desire for originality.
#2). As suggested, both B&S and S&K (
) make a mount the fits into the rear sight base which is usually banded around the barrel on Mausers. Did anyway. It permits you to mount a long eye relief scope ("pistol scope") well forward of the action. You might have to remove the front sight blade temporarily or learn to ignore it. This is the "scout rifle" concept that Mr. Cooper championed... Short, light, scoped battle rifle with which a well trained soldier alone could keep more organized (ha, ha) troops at a distance as he fled...
#3). The other option of this type, there are mounting systems that clamp around the rifle. Around the barrel. Around the receiver. One outfit uses the bolt release(??) Some require alot of wood removal from the stock to make room. To keep the original stock original, you pick up a 2nd stock and cut it out.
As said, don't over rate a scope. If you have mediocre eyes, then it helps. If you have good eyes and good shooting technique, then the scoped rifle won't do alot better than good iron sights. But you do have to know how to use iron sights and scopes are easier...
If you can access copies of the Gun Digest Annuals--some libraries, they have things like this listed and discussed in the back among sights and optics in the years that major military rifles arrived surplus. luck
