With this 21 shot rubber band shooter, you'll be able to rain hellfire (hell rubber?) down on your competition. This is a completely redesigned version of my earlier rubber band shooter with a vastly simpler trigger and indexing mechanism, and more stretch for longer shots.

The mechanism uses a pawl and ratchet for turning a worm gear that both advances the magazine and releases each band. Pulling the trigger causes the worm ¼ turn, advancing the magazine by one tooth. The leading edge of each of the 4 threads on the worm is what pushes each rubber band off of the nub above each tooth gap.

Assembly

1. Remove the small built-in support that sits in the trigger slot.
    
2. Insert the trigger into the slot
    
3. Slide the U-shaped clip over into the notches in the trigger to hold it in place.
    
4. Slide the pawl into the slot at the back of the shooter and place the hole in the end of the pawl onto the post on the trigger.
    
5. Screw the worm onto the back end ot the shooter with one of the screws.
    
6. Hook a small rubber band between the hook on the trigger and the hook on the frame.
    
7. Screw the tip of the magazine into the front end of the shooter with the second screw.
    

Play
You are now ready to load the rubber bands. The stretched length of the bands is about 280 mm and you can use any 1.5-3mm wide bands that will stretch that far.

Start at the right side of the magazine. Loop one end of the band over the nose of the magazine and then hook the other end over the little nub above the gear-tooth gap. The 3rd photo shows how it looks as you progress.

Now pivot the magazine around so that the left-most tooth engages the worm. Each pull of the trigger should advance the magazine one tooth and release one rubber band.