WW2 Plane with most Firepower?

There were some B-25's fitted with a 75 mm cannon.

 

Isn't it strange that a twin engined medium bomber can fit at most 12 forward-firing guns (belly and dorsal swivels not counted), whereas single-engined fighters can carry 8 .50 cal, or 12 .30 cal in the first place?

 

It's more about weight.... while they had only a few more guns they had a lot more ammunition for those guns. Compare the A-20 Havoc, B-25 Mitchell and A-26 Invader.
The A-26 was probably the hottest Medium/ light bomber Attack aircraft to come out of the war. Big difference between the R-2600 and the R-2800 engines.

 

A bit of a logical flaw there. Just because they fitted 12 forward firing guns doesn't mean they couldn't have fit more. For instance there ere some test of P-38's with one or possibly 2 gun pods carrying 6 M2's I believe. Those could also have been fitted in some numbers to medium or heavy bombers if there was a perceived need.

 

Meanwhile, in the Soviet Union...