I had to return the item because I had purchased the wrong one. But, it would have done fine for a .22, I just grabbed the wrong one when I needed one for an AR.
The use of these bases allow you to mount any full size scope onto a .22 rifle that has a dove tail scope mount milled into the top of the receiver using standard Weaver style scope rings. They look good and work great too!
I bough this adapter to go on my crossbow for a weaver scope base. It was easy to install and fits fine in fact I bought two just to have and extra in case I needed one.