Oh!
Well, Ruger used to sell target block 1" rings, and included a set with the #1 single-shot Target/Varmint rifle that came with target block mounts.
Don't know if you could still find any or not.
I also have a friend that just modified a set of air-rifle dovetail scope rings to fit target scope blocks. Don't know all the details though, but he got it to work.
rc