Sometimes J-B can be a big help if you have a large scope mounted on a factory action that uses small 6-48 screws to secure the rail.
I recently built a "Custom" on a R700 action. Only .223 caliber with a NF 12-42-56mm NXS on top. Would get "multiple groups". 3 in a single hole then 2 in a separate group. 10 shot groups did the same with two sets of "bugholes" on the target.
No amount of torqing, re-torking, would eliminate this.
I finally removed the rail, de-greased it and the top of the action, applied some J-B weld, and secured the base to the action. Not "Bedded" but "Bonded".
Result? No more multiple groups and the rifle now shoots Sub .25 MOA at all distances I've shot it at.
Did the same to my .308 and a month ago had to remove the base. The screws came right out (I waxed their threads before "bonding") and gave the rail a smack with a screwdriver handle. Popped right off. I noticed that gone were the usual rub marks I saw on all my other rails when removed for one reason or another indicating that they'd been moving under recoil.
Took only a few moments to remove a few bits of epoxy that remained stuck to the action by using the square back edge of my pocket knife.
I wouldn't do this with the ring to base mounting or likewise on the scope. If the scope is slipping, try some fine ground rosin. If the rings are slipping on the rail, get some rings that have Picatinney LUGS on the bottom like Seekins or Vortex. The lugs fit the slots almost perfectly and don't allow for any movement.