The M2 is nifty, but ammo can be tough to find. I'd get a Hummer and stick with head shots. Be careful shooting up! Even tiny bullets go pretty far. I gave the aerial stuff up for fear of plunking sumptin' down range.
Can't do better than the CZ for the money you're talking. Again, if money's tight, look at a Bushnell 4-12AO airgun scope. I put one on an RWS 54 and it's held up to the considerable vibration that gun generates for nearly 1000 shots so far, and the adjustment seem to track pretty well. Today, I ran the elevation around two full turns and back, and it ended up where it started. About $130 from Amazon. If you've got the bucks, the Leupy rimfire is very nice and would be my first choice.
