I'm a big fan of 'The Slingshot Channel' on youtube. Joerge Sprave lives in Germany and is about the coolest, most laid back and ultra smart guy that makes all these cool things.. mostly, can u guess?

SLINGSHOTS

but he also does vids on other cool stuff like this 'not-a weapon' crossbow/gun ..

Unlike most crossbows, and like most slingshots, it fires these steel balls..

Ouch! Imagine getting hit in the face with one of these!

Here's some more pics showing the slinger..

This things shoots fast!!

It hold many steel balls at once and you would think it needs to be reset and the the string pulled back each time before you shoot, but the ingenious design makes it easy to just re-cock using the frame..

This close-up is showing the firing mechanism which is snug against the loaded steel ball, so their is no slap or wiggle.

Finally, here's the vid so you can check it out. Joerge explains it much better that I can. (and you can see it in action!)

thanks always to youtube