A simple BBMG, or ball bearing machine gun, is one of the most satisfying projectile devices that can be made at home. A version known as a ‘cloud BBMG’ typically uses a pressurized air supply to blow BBs around an enclosed container at random until they are sucked out the only place the air can escape – The barrel of the gun.
There are many advanced designs, but for a cheap and easy project we can make a very functional 6mm airsoft pellet firing BBMG with a soda bottle, automotive brake line, and several air compressor fittings. The entire process is demonstrated in the following video.
While the above design is extremely effective, it does require a direct line to an air compressor to fire. This is a limitation that makes the machine gun not very effective in any actual airsoft games. In the following video I show how to modify the original BBMG design into two versions that can be fired without being tethered to a compressor.
Each of the three versions shown have their own advantages. Take a look, and maybe you can come up with your own. Stay safe, and remember your safety glasses.