Via BBB, we have this interesting tidbit in which Metal Storm announces plans to put some of its hardware on an unmanned helicopter, the Dragonfly DP-4X. Metal Storm is the company with a 36 barrel proto-type that has achieved fire rates for 180 rounds in excess of one million rounds per minute. A 40mm test device (which is the same size as would be put in the UAV) has achieved a single barrel rate of fire of over 20,000 rounds per minute. A UAV packing one of these could lay down some serious smackie.
I suspect that another advantage of this technology is that it’s completely electronic. No moving parts are required to fire the weapon. Moreover, the firing rate is completely controllable - every single round can be fired on command so the operator has complete control. It’s definitely cool.