They are Krieghoff-type slide-on mounts. Each mount has a lever which cams to flex the dovetail "male" onto the female base. Not made anymore that I know of (possibly AKAH or Reckenagle) and a slim chance of finding any used that fit. You do see them on Ebay from time to time. Probably a very expensive custom job is the only sure way to use them. That said, they are one of my favorites on a drilling because there is no bulky interruption of the shotgun rib.

Best,

C.

Last edited by C. Kofoed; 05/09/11 12:21 AM.