Range Update. Installed the Leatherwood CG I received from Ironsights. 98% line up. Torqued everything down as tight as possible. Mount performed as designed, no looseness after about 160 rounds, stayed tight on both thumb screws. I screwd down by hand, and then about 20 degrees with pliers. I initially tested under a Weaver K2.5. rifle shooting high required alot of elevation adjustment, but zeroed in fine and held zero. Can't say I'm as happy with the performance of the ART/MPC. AAMOF, Im quite disappointed. Wasn't able in my time allotment to get a solid zero. Will try again. Nevertheless, mount setup is solid and a keeper.