The Dillon Aero DGP2300 Gun Pod combines a 7.62mm M134D-H gun with a 3,000 round magazine. How long does it take to shoot 3,000 rounds you ask? Just 1 minute.
The system is entirely self contained, so it can be mounted on any aircraft that can handle weight, rotational torque and recoil of the gun (190 lbs of recoil). It has its own battery which can be wired into the aircraft to trickle charge.