this gun is built along with the simple semi-auto rbg. i should have put those two on the same page but i want to widen my category a little bit :-D. it has a basic mechanism and is very simple to build and to use.
you just put as many bands as you wish on the gear in the middle ( but not more than 7)
pull the trigger and the bit stopping the gear move away. the gear spin forth and the rubber bands splash forward all at once. that's why i called it "sawn-off shotgun).
this might give you a good impression of the size. sorry about the messy background. (it's my bed, with a vietnamese-english dictionary and smithsonian institute's "flight" on it)
the gun use the same small bands like the simple semi-auto. the range is pathetic, about 30 centimeters only, but it is still fun to play with. i'm working on a rbg with fire mode selector, hope it will be finished soon.