I'm swapping optics between my 308 and 6.5x06 . The 6.5 originally had a Leupold STD mount (see pic) with a dovetail in the front and flat base in the back. I couldn't find 34mm rings to match the existing STD bases so the local gunsmith swapped them for Weaver Top Mount Bases (#48227 and #48045). When I installed the bottom half of the rings on the bases , I went to level the rifle and noticed that the two bottom rings aren't level with each other. It's possible the original mount has been the this way all along, I didn't reinstall it to check but now I need to know how much this matters. I understand that the optic needs to be in line with the barrel and the reticle needs to be level and all but how much of a difference does the cant of the ring make? Thanks for your help !