I have yet to see a satisfactory .22 WMR semi, all seem to have either accuracy or function issues, except for the 10/22 Mag, which was heavy as sin with the steel receiver, kinda took the fun out of having a 10/22 platform. Given your preferences for a non-bolt rifle I'd look for 1) Marlin 57M (been there, done that, traded them both off and regret it every minute) or 2) Win. 94/22 Mag. (as above, still wish I had it back too!, OK, I'm not a fast learner). A distant buddy had the CZ and had issues, function wise. I've not owned one at this point. If you NEED an auto I believe Magnum Research still makes a 10/22 like actioned one. In any case $500 is going to pretty much be the starting point for the Marlin, Win, or MR in really nice shape. At least the ones I've seen in my neck of the woods.