The drum on this thing is too large, it makes me nervous.  Think of the children:

Dude’s voice and delivery sounds like a computer.  I thought this was maybe the same guy who made the snowball assault weapon with a leaf blower, but I was wrong.

If you build one of these make sure to practice the regular rules of gun safety.  Can you imagine how embarrassing it would be if you had to go to the doctor and explain how a cheeseball traveling at several hundred feed per second detached your retina?

Gat tip: Steve