Here's what happened to me..........
338 RUM 300 SMKs @ 2730 or so.
Burris insert rings. To get the scope to hold I had to hawg the ring torque so much that the nifty little wrench looked like it was threaded. That is, it was twisted about 3/4 of a turn.
That worked well for about a year then accuracy went bonkers.
Cause was the windage adjustment on the rear mount sheared.
Went with double dovetail mounts (rear same as front)--------No further problems.