Huvius, thank you for that. The pin you refer to is actually an eccentric cam and is used to draw the down the foot into the mount. The grinding of the cam has to be pretty accurate so that the lever ends up horizontal without having to use excessive force to seat the ring. Thanks again, it was actually just the rear foot part that I wanted to know about, having not seen one before. Thinking about it, the inside rear face of the the rear base is most likely slightly convex so that the taper on the hook of the foot touches at one point when the rear ring is pulled home. Otherwise they would have to exactly match the tapers, which would be extremely difficult to do. Thanks again.

Waidmannsheil.