[quote][b]Posted by:[/b] thekman5 looks to me like a cannon[/quote] In a way you are correct, but if you're thinking of a gun that shoots ammo the size of a tank's gun then you are wrong. Anything that's shoots ammo a little bigger than 50.caliber is designated cannon, i.e. the 20mm cannon in Saving Private Ryan that the Germans use to shoot up the guys on top of the Tiger tank near the end of the movie. Anti aircraft guns are usually cannon, like the LAAG(Light Anti-Aircraft Gun) on the back of the Warthog.