I was trying to put a new scope on a rifle last night and I ran into a set of mounts I'v never seen before. They were a vertical split ring, at the top was a small round cap with a undercut groove under the cap that the two rings lock into. The only screws to hold the rings were two set screws at the each base to pinch the rings. When the mount is completely installed the ring looks to be one piece. I'll work on getting some pics. Is there a name for these mounts other then the four letter words I was using last night? Thanks.