Now I'm willing to let this one go, but the thing I wonder is..
Just how many shots can someone take before they get tired? I mean if it takes chakra, then a genin should only be able to fire a few shots before he gets tired, where as a chuunin or jounin could use more chakra for that. Perhaps add in some levels for that? If not that's fine too because they'd probably run out of ammo before they got tired.
More importantly.. if this cannon is on your arm, how is one to perform to jutsus? Unless the person can use one handed seals.. all the time. In which case, can they fire as they perform jutsus? Or does the arm cannon allow the hand open?
Good chart, and thanks LOADS for being so patient. Just clarify those things, and it's ready to accept