Step 1: Pencil Gun for School
First take a mechanical pencil and keep the spring in it.
Step 2: Pencil Gun
Now take a spring from something else then put it in the cap of the pencil then tightly put it back on to see if the springs big enough
Step 3: Almost There
Now just unscrew the top right before it comes off
Step 4: Ready to Go
Now just push the back
Step 5: Pencil Gun
Now just watch it fly and try to get the spring stuck in the cap so you don't lose it!