Light rifles with heavy scopes do suffer from this. You want to increase friction in the joint. Scope tubes and rings are anodized, this is a hard slick surface. Lap the rings to get to raw aluminum and/or bed the tube. This will eliminate the issue for the most part. The other element is the brake. The concussion from an aggressive brake will loosen screws. Pinned rails, loctite, ext. help. I prefer integral rails when I can get them.