Spent much of the afternoon today at the sporting goods store owned by a friend of mine. I bought a new .308MX there a couple weeks ago and came back to have a scope mounted. What an ordeal. After many attempts at different bases, rings, scopes, and screws my friend decided either the holes were slightly off or the receiver top was not completely level. We settled for Leupold QR bases and Burris medium rings with shims. I wanted low rings but had to settle for this for now. Anyone have similar experiences or a formula that works?