The late Butch Fisher made an unique piece for his rail base to sit on. It was a piece of industrial rubber belting, with cord inside like a tire, that was larger than the base of his rail. He milled recesses into its top, that fit stainless disks that had cones cut into their tops to match the leveling points of his rail base. He glued the disks into their recesses, using the base as a fixture to precisely locate the disks, and to apply pressure while the glue dried. I spoke with him about this a number of years back. Evidently this made the rail quite secure on the bench, did not weigh too much, and with it in place, the rail performed well. This all goes back a number of years to when this issue was being discussed and I believe it was Del Bishop that mentioned Butch's setup to me, and I gave him a call to get the details. A friend had Butch build him a bench rifle, and later bought a couple that he had used to compete with, one of which had been used to set a state record. The workmanship was excellent on all of them.