Since forward firepower seems to be on everyones want/need list Lets bring in the succesor to the Havoc, the A26.
Depending on the variant it had probably the most (in terms of individual guns, including the 2 from the turret, a total of 16 .50's ) forward firepower of any aircraft in the war.
Original production models were built with 6 gun noses and provisions for 4 underwing gun pods each containg 2 .50 cal's fed by magazines in the wings. Additionally the upper turret was designed to be locked in the forward position and slaved to the pilots trigger. Later models had 8 gun noses, but by then it had been determined that the pods created too much drag and were eliminated in favor of 6 .50's internally mounted in the wings like those of most fighters.
Furthermore the Invaders' interchangable nose section was capable of being outfitted with a variety of armaments of the day including the 75mm cannon that became associated with the B25