Big
FWIW my brother in law just bought a light 300 RUM and he's had Leupold rings, old Redfield rings on and both of them let the scope slip. We are somewhat at a loss other than going to something tactical like badger for more surface area. It may not be the fault of the rings and inserts as I've used them up to and on a 300 wtby so far with no problems. It may be the nature of the beast. I know that the 338 Edge I'm having built the smith suggests other than standard rings for the scopes.
FWIW my brother in law wants to loctite his scope in place......
Let us know what works, I may need the info also.
Jeff