Hey guys, this is my first instructable! Make sure you read the whole thing before building because i backtrack a bit. Comment on improvements or flaws and enjoy. Check out my airsoft grenade instructable at http://www.instructables.com/id/Airsoft_Grenade_5/
A Fully Automatic Gun that can shoot 6mm BB's. I actually haven't done this yet, but it should work. IF it does.... I AM NOT RESPONSIBLE FOR ANY ACCIDENTS OR INJURIES THAT MAY OCCUR WHEN USING THIS GUN, AND I STRONGLY RECOMMEND THAT YOU DO NOT MAKE THIS GUN.
Step 1: Materials
The gun consists of a wooden frame, a 9v battery, a 9v motor, a 7mm tube that won't bend easily (I'm going to choose aluminum), a wooden trigger, wire, a small wheel, a wooden clip, electrical tape, 6mm BB's, a drill with a 7mm bit, some hinges, a spring, and some aluminum foil.
Step 2: The Insides
Here's a diagram of roughly what the gun should look like. You don't have to have two handles. I forgot to add a door for the batteries to be switched out, which would make life easier.
Step 3: Frame
Take a piece of wood and carve it into a gun shape. Make it wide so that the components can fit inside. Then take a 7mm drill and drill through the spot where you will shoot, almost all the way to the other side of the block. Once you do that, cut it in half so that there are two symmetrical gun shaped pieces. After that, take each piece and cut some of the bulk off of the inside while keeping the edges the way they are (it's hard to describe, so look at the picture).
Step 4: Battery hole!
Cut a hole a bit bigger than a 9v battery into the handle of the gun and keep the piece of wood. Take a hinge and attach it to the gun and the piece of wood so that it swings open and closed (don't worry about it swinging open, you'll be holding it down when wielding the gun.