i'll send you the drawings. they're in PowerPoint. Oh, and I won't be able to "stop by the local machine shop" until I get back from Iraq in October. I drew "plans" with a rail on each side, but putting one on the bottom is easy. Essentially I drew a 1" diameter 2-4" long tube for the magainze extension to slide into, with a "welded" spacer bar to cover the gap between the mag extension and the barrel (about a 1/4" in most cases) running the length of the bottom tube, on top of that, there is a 1/2" diameter 2-4" long "half pipe" with the picatinny rails on the left and right. i made the top half of the clamp two pieces so the clamp slides onto the mag extension, and under the barrel. the top tube is 1" in diameter, with 1/16" shims provided to fit the barrel as tight as possible. it screws into the bottom half with 4-6 screws (depending on wether i make the whole thing 2" or 4" long) with the mating surface behind the picatinny rails. the rails would stick out from the barrel about a 1/2" on both sides. if you put the rails on the magazine extension, they're closer to the center line of the gun, since you don't have the screws behind the rails. this also puts the rails (and subsequent attachments) inline with the forend. if you want the "plans" i'll email them to you.
