The multishot for the AA S200 is a little clunky, but it does advance on its own from what I remember. Steve C. had a S200 that I shot quite a bit on a trip to his place, sweet guns. I also owned the Tau-200 which is another variant of the S200, but CO2 powered and setup for 10m shooting. Daisy also marketted a version known as the Daisy Valiant. That similar action is on a whole bunch of guns, including some 10M pistols, best trigger in the world almost.
Edit: btw, the new S200's have a one piece stock.