I built a pen gun that shoots right when you push the clicker thing.
Step 1: Materials
You will need a
click pen with spring and the clicker things, doesn't matter what kind,
and keep the top so you can make it not noticeable
and the ink so you can push it into place to o shoot.
Step 2: Getting Together
Push it in in the order that the picture shows.
Step 3: Reloading and Shooting.
To start you need to put together the the things in the end of pen to shoot. To shoot push the click. Have fun.