This is the easiest gun i know it only takes a minute to make and all you need is a pen!
click pen (with spring)
Step 1: Take It Apart
take it apart. it is that simple
Step 2: Stretch Out the Spring
stretch out the spring but dont do it to far or else part of the pen will snap (see picture for how far you need)
Step 3: Putting It Together
see pictures just put it together like a regular pen
To fire, unscrew the cap until it goes shooting forward!