Video: DIY Mingun

The mini gun was constructed using a repurposed cordless saw motor and some high intensity LEDs to create a muzzle flash look as the barrels passed in front of the lights. The basic construction is relatively simple- with a standard 1/2 inch copper pipe serving as the main support for lightweight tubes (barrels) that spin and emit light when they pass in front of LEDs. A cheap cordless drill - something from Harbor Freight - is the easiest way to start.

Source: Make Projects