Ah, Buehler rings, how I miss 'em. At one point in the '70s I lived only a few miles from their operation in Orinda California and I was astonished to find it not much larger than a garage. Good times, that.

Anyway, fitting Buehler vertically split rings is not at all like fitting the Redfield/Leupold & other current horizontally split jobs. They can be a pain, but when set up right they're a peach.

What is supposed to happen is you fit the rings to the individual scope by playing with the shim thickness at the top of the front ring until, with the ring on the scope and both top and bottom ring screw tight, the projecting spud is a nice snug fit into the round hole in the front base. The directions supplied with the rings gave a measurement for the spud diameter that you were supposed to achieve.

Then, knowing what shim thickness you arrived at to make the front ring fit well in its hole, you peel laminations off the shim in the rear ring to the same thickness. This is supposed to result in the bottom surface of the rear ring being a perfectly flat fit onto the rear base when the rear base screws are tightened.

Next, with the lateral screw in the front base loose, you insert the front ring spud into the hole with the scope at a right angle to the mount (the rear of the scope to the right of the rifle), seat it to the bottom of the hole and swing the scope clockwise until the rear base lines up, pretty much like the Redfield/Leopold system. Tighten up the rear base screws to a happy point of windage, then finally tighten that front lateral screw. There's an interference fit between the spud and lateral screw that holds the front ring down, much like the rotary dovetail in the R/L system.

If the shims are set up correctly everything tightens up square and secure, and there's _no_ gap at the top of the rings. In fact, the shims supplied with each set of rings were actually machined along with the top of those rings and had exactly the same contour (as long as you remembered their orientation) and a correctly set up ring looked like it was one piece - you could hardly see a seam at the top at all.

Elegant, but finicky. The shims get lost easily, bend easily and there's no way to make the originals thicker once their laminations are peeled apart. It's easy enough to make replacements out of solid shim stock, but guessing what thickness they need to be is a problem and it's difficult to achieve the seamless fit the originals had.