This DIY electric centrifuge BB gun may be from a 1963 issue of Pop Mech. And it's more of a toy than the full on killing machine that the Dread centrifuge gun is. But that doesn't mean it can't hurl pellets at ridiculous velocity. According to the article, the muzzle velocity will reach 5,000 feet per second, which is better than a rifle. Click on the image for the full schematic.