Even for that sort of application, I would think the limitted overall capacity of the system would severely curtail its usefulness. Correct me if I'm wrong, but there are already guns whose sustained firing rates (from an arbitrarily-large beltfed megazine) are well over a thousand rounds/minute. Ganging those together would seem to provide a much more useful increase in firepower than would this 'metalstorm' thing. Even if there's an incoming missle and your goal is simply to unload as much lead as possible in five seconds, a group of miniguns would seem to be just as capable as the metalstorm, and unlike the latter would be ready to shoot again if another missile followed the first.