I had one of those! I modified it with a metal disc on the back of the cocking mechanism to make it easier on the hand, and put an extended length magazine on there (you had to aim up between shots so the balls would roll into the chamber)

pic: http://www.vintagerex.com/museum/NSG%20-%20National%20Surviv...

I too dropped out at the start of the arms race. Just couldn't afford to keep up.

Yep, we had a bunch of these we rented out at our paintball field when I worked for a small company in high school. It was a blast. Working the "concession" stand (selling paint, renting equipment) wasn't that much fun, but I got to referee an equal if not greater amount of time (our field had a central area with an abandoned building and we can climb on the walls to watch multiple groups).

Also I could play free whenever I liked (off hours).

i had one of those too, it was super fun! my favorite was a clip fed pistol that was really fun, but totally innefective :P

one of my friends who will remain unnamed wanted to play "Force power paintball" one weekend camping, he grabbed a stick and wanted to "test out his force powers" deflecting a paintball. let's just say he's no jedi...