This came up for me recently when I acquired a Barrett FC. Initially, I had a rail on it so tried some Weaver rings I had on hand. I don't use tactical anything so I was going for as low as I could go and it seemed that this set up intruded on my ability to load the magazine. I didn't really notice anything hitting rail or rings but the thought of keeping the right side as "clean" as possible occurred to me. I have since gone with Talleys on the Barrett.
