CZ Slavias are very popular low power plinkers, and personally i'm a fan of just about everythign CZ puts out--great value for dollar. the 631s were discontinued about a year ago and became quite hard to find, but it looks like there are "new" ones readily available via gunbroker. go to link below and type "slavia" into the search...
http://www.gunbroker.com/Auction/SearchForm.asp
Beeman R7 is another great shooter, very accurate and popular for all ages at our local FT club. some info:
http://www.straightshooters.com/beeman/bdr7.html