Cloud BBMG

It's actually a pretty simple concept. Although not nearly as effective as a vortex disk/block. If you have a small box, with a hole in one side leading to the barrel, and a hole in the bottem connected to an air sorce, and bb's in the box, you have a cloud chamber. When the air comes up from the bottem, it has one way to go, through the barrel, when this happens, it creates the suction effect, this draws the bb's up and into the barrel. If you build a full auto bb gun, this method is simple, cheap, and easy. But, so is a vortex disk and it works a LOT better. Seriously, go for the vortex disk.