https://www.instructables.com/The---jrP4-----Junior-Portable-Pnuematic-Projectil/
The __jrP4__ - Junior Portable Pnuematic Projectile Propogator : 6 Steps - Instructables
The __jrP4__ - Junior Portable Pnuematic Projectile Propogator: I have wanted to make something like this for a long time, but couldn't quite figure it out....
juniorportableprojectilestepsinstructables