A friend brought me his Ruger MKII last night and asked me to put a Leupold single-piece mount on it. I told him I didn't think there was such a thing but he says he knows someone who has one. Anyone here ever seen such an animal? I can't find anything like that on Leupold's site but I did find an adapter that Burris makes but it's two-piece.

He might be confusing the Ruger round top M77 with his Mark II. Leupold makes a one piece base for the M77 round top.