Cool video! I have been thinking I needed a cannon for years after first seeing a bowling ball cannon. Those things are way cool especially shooting used balls. The finger holes get a wind whistle going and you get a woo-woo-woo sound all the way to the target area.
Thinking smaller scale I think a pool ball cannon would be more the ticket. One more thing on my bucket list that will never happen! I can see I need to take a little off of my break too, 150-200MPH is probably fast enough.
Hu