He epoxies the scope inside the rings. The inertia created by the recoil will cause the scope to move. It is like striking the handle of a pick on the ground. Eventually the pick head will come loose and slide down the handle. he puts a small dab of 30 minute epoxy on the inside of the scope rings, top and bottom, where the scope goes. The 30 minute epoxy will allow you time to properly adjust the position of the scope before it starts to set up. Not to worry, if you ever wish to remove the scope it will easily break loose. I have adopted this practice and all my scopes are epoxied in. I have never had a scope move since.
With the recoil generated by the 500, aluminum scope rings come apart after only a few rounds.