Re: Preventing ring marks
Good quality rings mounted on a straight base and torqued to spec should not leave any ring marks or need to be lapped. The Burris Sig Series are nice and a cheap/easy way to make up for base problems, but they're not nearly as strong, won't have as good return to zero performance, etc, as some of the higher quality tactical rings. The idea they are needed to prevent ring marks is just not correct.
I'm of the opinion that if you're reading this board, in the long run you're better off with a quality 20 MOA picatinny base and a pair of quality tactical rings than trying to make due with lower quality/cheaper/lighter duty stuff which you'll probably end up replacing eventually.