I accidentally happened to be at a local range years ago when a group had a machinegun shoot. It was unbelievable. I got to shoot some 9mm submachingun. I have no recollection what it was anymore. They had several belt fed guns. Even a Browning 50 caliber. I also got to shoot a single shot bolt action 50 caliber. It was before Barrett came along and I do not recall who made the gun. I do remember that you had to completely remove the bolt to load and unload it. It had muzzle blast that was unlike anything I've ever seen and I have a 460 Weatherby.
Thanks for posting this video. I wonder how the guy with the 20mm anti-tank rifle got that by the BATF? The good ol Gatling gun they showed is a darned good thing for us shooters who want full-auto that's not considered full-auto too. The motor powered Gatling's - well there's nothing quite like them, is there?