I little side story:
I was at the Shot Show when Burris introduced their Pos-Align rings, and attended their event sitting across a table from Jim Carmichael, who I have to say made a tremendous impression on me. The fellow at the podium said that he had gotten the idea while working on a center support and bearing of a two piece pickup drive shaft, which made me smile a bit since I was well aware of the Jewel rings and was pretty sure that they had to be. Not too long after that I called Arnold and asked him how he felt about their stealing his idea. He laughed, and explained that no one could patent the idea because there was an old patent that had expired before he came out with his. For those that like this system, Burris has recently come out with a new tactical version with dual steel clamps, and are available up through 34mm, with offset inserts extending to +- .020. For the guys that shoot long range having this degree of offset available will, I think be quite welcome. While the loose clamps are steel, the rest of the ring is aluminum, except of course the inserts. List prices range from $108- $156.