Oh, joy! A real source of info on parts, etc! Just finished building my DR, and I found that a 1/2" square key stock milled to a vertical taper makes a nice quarter rib, and if you mill dovetail grooves in the sides, and little 3/16 recesses on the top where you want scope rings, a Ruger ring clamps nicely on the quarter rib. Will try to figure out how to post a photo.