I had zero luck trying to locate factory rings to fit these bases. I bought a set of Leupold Super-High rings, drew up a set of plans, and went to visit my tool and die maker friend who has a Bridgeport mill in his garage. Here is what we produced. I just finished rust-bluing them a few days ago. One half turn of the levers releases these rings or locks them down like they were welded on. The gun shoots VERY accurately with this Kahles 2 1/2 power scope mounted.