We made these miniatures cannons on a Mori mill and a Haas lathe.
They have stainless steel barrels and anodized 6061 aluminum bases, with stainless or brass hardware. They pack quite a punch!
POCKET ARTILLERY - ***BOOM***
[ame=http://www.youtube.com/watch?v=rEvlNDczJ2g]Pocket Artillery Mini Cannon Test Fire - Coke Can - YouTube[/ame]