The centerfire Leupold 2-7x33 scopes will work on them. I've used the Vari-X and the VX1. IMO they're not too big for the rifle and are brighter with better eye relief and faster target pick up than the smaller rimfire scope. Leupold will reset the parallax to rimfire distances for around sixty bucks or you can do it yourself. There's a good thread on this at "Rimfire Central". It's not that hard to do. I'd try it before resetting it. It might work fine as is.
The old M8 4x28 will work on it too. At that low a magnification there was no need to change the parallax setting on mine.
