my friend once knocked a lense out of my glasses with this
while I was still wearing them (This is a mod to thiswith straws)
Step 1: Gather Materials
two small straws,
hobby knife or scissors.
Step 2: Make Ammo Cartridge
then cut one at a 45 degree angle.
Step 3: Make Barrel
Step 4: Final Assembly
when firing you might need to move the straw around a bit to get the bb's moving