I love making things out of just about anything, the coolest thing I ever made was a coil gun. But seriously, this is actually pretty freaking awesome! A youtube user that goes by the name of Nighthawkinlight made this UZI stile BB gun using a 20 ounce soda bottle and an air compressor. The video above teaches you how to make one at home for under $15, and from the looks of the video, this gun can cause some damage.
The concept is pretty simple, you push in air on one side of the bottle and as the air is trying to escape, it pushes out BBs with it. The speed can’t be that high, and I’m sure is not that accurate, but this is an awesome simple and easy to do project for when you’re bored at home.
The only bad thing is that you have to carry an air compressor with you on your back, unless you somehow manage to attach a Paint Ball CO2 canister to make it a bit more compact. Even then, the amount of air exiting the gun is to much to really keep it going for an extended period of time. YouTube, via Geekologie