What are some of the common cannon failures?
For manufactured cannons (Swampy type): Crud in cannon from sinking, bad bb in breach/magazine/barrel, broken barrel, corrosion in cannon from sinking and letting water sit. From home made cannons, all the above plus: bad solder joints that leak/have solder blocking/fall apart, flux inside, bad machining on brass parts, springs/pistons that jam (most common). Also for all types, bb dents in barrels, magazine, and lift tube.