I as tinkering around and made a semi-auto one.

Oh and.. I know it's weak, because I made it mostly for scientific design, not for performance. So feel free to take it farther and make a real shooter out of it. : )

Step 1: Hopper and Front

this is the hopper and front of the gun. like the last one, the gray connectors and blue spacers are the hopper ;and the black piece under it is there to stop bullets from falling through.

Step 2: Firing Thing

the yellow rod is what hits the bullets to make them go flying; and the chunk on the right is the handle. that red connector with the green rod on it is the trigger.

Step 3: Important Piece

this is connected to the trigger and pulls the firing piston back.
(sorry the picture is blury)

Step 4: Another Important Piece

this makes the piston release as you pull back the trigger

Step 5: Hopper + Firing Thing

connect the black rod and the orange connector to: the yellow connector and the white rod on the hopper piece respectively.

Step 6: + Trigger Piece

this is a lil hard, put the red rod into the grey pieces sticking out of the shooting thing. then lift it up a little and attatch it to the trigger. then put a small black piece between the trigger and grey pieces for stability.

Step 7: Rubber Bands

put a thick rubber band on the firing piston and a thin one on the trigger.

Step 8: + Thing

put that thing on the blue rod comming off the hopper (this view is from the top of the gun)

Step 9: FINISHED!

ok now you're done!
load 7 small green rods into the hopper and hold somwere on the back (front too if you want accuracy and a more confortable position) and pull the trigger until it shoots. make 2 and use one in each hand ;-)

sorry for the sloppy instructions and any misspellings "-_-