Now here's a guy who loves his guns! I'm not saying he's a violence freak or anything...
Though I wonder if this is faked? I find it hard to believe that any handgun can fire that fast, big magazine or not. Also the Glock 17 is said to be a semi-automatic, meaning that while it loads the next round automatically (I think with the recoil), it requires one pull of the trigger to fire one bullet, it won't keep on firing.
Googling around a bit, some claim that "fully automatic handguns are out there", but it seems to me that overheating and handling the recoil would make them dangerously impractical.