Hi. I found this 11 mm to 20 mm base adapter on Amazon. It is low profile and just snap onto your scope ring base and snug it down. It worked great on my PRod and Crosman 1701P Silhouette. About $13.
I use the smaller square ones that are a single weaver groove each on one of my rimfire. An excellent way to convert an existing scope and ring combo to a dovetail gun without increasing height over bore too much
