I bought a very used 22A with a 4-inch barrel for $160 (great price in CA). The original owner had never cleaned it or changed the buffer, the rail screws were screwed down with an air ratchet, and the breech end of the barrel was all chewed up in every way possible (feed ramp, ejector port, dry-fire damage). I took some 800 grit paper to the breech, discovered it was not heat-treated, so it sanded very nicely, made a buffer out of some 1/16th inch delrin, loctited the rail, and headed for the range.
The gun shoots like crazy. With CCI mini-mags it shoots flat to 100 yards. It shoots as good as my k22!! I assume that a lot of the astounding accuracy is due to the un-heat-treated barrel. I just ordered the 5.5 bull barrel with hi-viz sights ;^)