Bob, The scope bases were milled out of a piece of steel Weaver base stock, made by a company called Moulds, and bought from Brownells. Mortises were milled into the quarter rib to accept the bases, flush with the top of the rib, and 8-40 flat-head screws are used to anchor the bases to the rib. I'm pretty sure that one of the photos above shows this fairly well. Matting the top of the rib with the 50 LPI checkering file camouflages the seam between the bases and the quarter rib so well that it's virtually impossible to see it in person, let alone in a photo. Finished weight, with the scope, looks to be just on 8 pounds. I was hoping for 7 to 7.5 but it's darned hard to achieve that weight in a double. Those Vari-X III's are great scopes. I have one on each of my doubles. Too bad that Leupold discontinued them. I have no idea how the VX III that replaced them stacks up for quality against them.