-Drill w/ bit(I used a 13/64 bit)
Step 2: Taking Apart the Pen
Take apart the pen so the ink tube w/ tip on it and the outer part are seperated.
Step 3: Drilling the Hole
Drill a hole in the middle all the way through so the ink tube can fit in it. I used a 13/64 drill bit
Step 4: Cut the rubber band
Cut the rubber band in half.
Step 5: Attach the rubber Band
Attach the rubber band at the top with duct tape. Run it down the outer body so it covers the whole, and attach another piece to hold it down. Make sure it is tight. Cut some more duct tape and make the attaching parts neater.
Step 6: Using The gun
Put the ink tube through the whole so it touches the rubber band. Pull back and shoot!