My best and latest attempt at an air cannon. Powerful for it's size due to relatively high pressures, and specialised valve.
Fires everything from potato and paintballs, through marbles and ball bearings, up to specialised ammunition optimised for results on impact.
I stress, the launcher is NEVER used on live targets with any ammunition, it's simply too risky. People who think paintballs could never do damage should take note - when they go fast enough, there is real potential for injury.

This is the most complex video I've ever compiled. I know it's said too often, but if you like the video, please rate it and leave a comment.
Update (6th Nov 2008): There is another cannon in the pipeline. Keep an eye out for that.

I cannot make plans available for this cannon, but if you visit either of the two links below, you can get advice and guidance on making your own air cannon:
http://www.spudfiles.com/
http://www.uksgc.co.uk/

Anyway, watch and enjoy.
Please ask my permission before using or copying any parts of this video. (less info)