Re: Solder on scope rail?
I would speculate you don't see it often because we've all had it beaten into our heads that if anything hot gets near an action it ruins it.
True, if you turn it into a 3 mile island cooling rod your probably going to draw out some of the hardness.
Sights are soldered onto barrels every day with no ill effects. Just don't go bezerk with the torch and you should be fine. Understand also that if you get a torch anywhere near a blued/coated finish it will ruin it and have to be done all over. In this case you shouldn't care because you'd have to get all the parts to bare metal anyway.
Make a heat sink. Turn a big ol fatty chunk of brass so that it slips down the receiver bore and screws into the action at the same time. leave a portion sticking out past the action as well. Just be very careful with the heat up in the receiver ring. Just hot enough to get the solder to flow. Use a solder with a low melting point. If you combine this with screws it's not going to move unless you habitually toss rifles from 10 story windows.
Another trick. When you mount your scope, if its a boomer magnum, use a dab of coarse lapping compound where the ring/scope meets. It'll bit the tube and the ring when clamped and it's not going anywhere. Best part is there's no epoxy mess to deal with if you ever pull the scope off for something else. Just wipe it and go on with life.