The insanity and ingenuity that can be found in the firearms world never ceases to amaze me. My latest personal muse is this black-powder machine-cannon suited for .36 caliber (cannon) balls. Using 4 rows of eight barrels, this portable wonder shoots nearly as quick as the MetalStorm.
Its firing mechanism is fundamentally rudimentary, but works like a charm. In fact, at about 25 yards, it fires a pretty good pattern.