The fact that you used to different set of rings and heights means it is a scope issue. The rifle in question has a small ejection port andwith it being on the wrong side makes that focus problematic. I would mark the focus knob with lipstick and put it on smoothly and then see where the case is hitting. It might only be a few thousandsif you move the knobback or forth or in the worst case scenario. That fat 300 wsm case is not helping matters either.