Degrease the receiver surface, scope tube, and every (and I mean EVERY) shred of surface on the rings, screws, and screw holes with rubbing alcohol or brake cleaner. Then use blue loctite on the screws. Everything is coated in a thin film of oil when it leaves the plant--Look at the packaging the rings came in...nine out of ten times it's oily in the pocket where the rings were rattling around in. You will save yourself potential problems down the road by doing this.