Great for airguns and rimfires - Hawke Sport Optics Shim Ring Inserts 25 MOA Set

They provide a simple way to add elevation to your setup. Be aware that one shim goes under your scope at each mount but none above. I assume that using a heavy hand when tightening your rings will end up denting your scope under the high edge. I had bought 2 sets to mount 1 scope but found that using a top and bottom wedge was not feasible when I mounted mine. Maybe if I had sourced longer screws... For that reason I wouldnt recommend it for heavy kicking guns, even though they are doing exactly what I need done on my Walther Parrus.