this has probably been made a bazillion times but i'm making my own version
Step 1: Materials
the materials needed are one fat rubber band, one skinny rubber band, scissors,and one BIC round stic medium pen.
Step 2: The Pen
first you need to take apart the pen. i couldn't take off the back end so i cut it off but that is not needed.
Step 3: Big Rubber Band
use the scissors and cut the big rubber band in half.
Step 4: Making of the gun
now take the big rubber band and put the 2 loose ends on seperate sides toward the middle of the pen. now take the small rubber band and tie around the big rubber band to keep the big one in place. i had a big rubber band so i had to put it towards the other end.
Step 5: Ammo/fire!
the ink canister is the ammunition. put it through pen against the rubber band. pull back the ammo and the rubber band and let go to launch.