JJS,
No problems. I am using plain jane Leupold 2 piece bases and rings, the type with the windage adjustment on the rear base. I have a Leupold 4.5x14x40mm on my 300 RUM. Not a very heavy scope. I would bet that the heavier scopes want to move under the recoil of the heavy recoiling guns (simple momentum).
I had thought about going to dual dovetails, but I have never had my 300RUM or 338 RUM (Leupi 3.5x10x40mm) for that matter, shift POI or have the scope shift. I am shooting both my 300 and 338 RUM's with this settup, without a muzzle break, so the mounting system and scope are getting the full recoil.
I may however, eventually switch my 338 RUM to Leupi dual dovetails, only because I intend to use it on big bears up in Alaska. Don't want to leave anything to chance.
Tony.
