It's awesome. I've always wanted to make something like this.
In Primary School (Year Six), the woodwork teacher saw me designing one and said "that'll never work sonny you don't have the skill and experience". I said, "I know i don't I was just designing it for fun."
He then took it off me and said "I'll make one, but not as near based off this crap!" He threw it in the bin.
When he built it after the first shot (He shot some toilet paper to test it) on the oval he drew everyone's attention.
(I was pissed). The next shot he said he'd shoot a marble at a cinder block.
Lights it runs off, and massive explosion the gun ruptures flies about 3m into the air and lights the wooden furniture on fire. He just looked at me and had that look in his eyes that was like Puck You!
I believe it's called Karma.
My guess is that the marble either gt jammed on a notch in the actual barrel or the back blew off, but I can't really remember that was 3 years ago.
Poo.