One crazy slingshot…err cannon?

I love the slingshot channel.  But this thing is crazy, it basically has a spiral inside the circle that spins the big ballbearings around and then fires them out at the end.  I can’t imagine building this thing.

http://gizmodo.com/turn-a-drill-into-a-shotgun-with-this-spinning-disc-of-1148139177?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+gizmodo%2Ffull+%28Gizmodo%29