Make a rubberband gun with a piece of paper

I made this gun in a boring class, and it can shot a small paper ball for 5 meters.

Materials:
-a piece of paper ( I teared it from a notebook )
-a rubberband
-some tape
-a ballpen ( something like the core also works )
-some glue

Maybe you need something to cut the tape.

Portrait split the paper to 2 parts from the middle.

Disassemble the ballpen, take the core out.

Roll a strip of paper with the pen core as tight as you can.
Glue the tip.
Pull the pen core out.

Roll another strip of paper around the striker.
Do not roll it too tight.
Glue the tip, too.

Make sure they can slide smoothly.

Pass the tip of the tape through the rubberband, then tape it on the striker.
Tape another tip of the rubberband on the barrel.

Fill a small ammunition in, pull the striker, release to fire.

I am going to make a auto refill one

Sorry for my poor English.