There's a guy on GLocktalk who owns a GE Minigun (only 4 of them are transferable in the US). At a rate of 6000 rounds per minute, he has save up a whole year and wait for a a good deal just for one session...
On one part of the video, one gun sounds like its farting. That must be using a shitload of bullets. It kinda sounds like those guns on the side of warships used to bring down incoming missles and things.