Both WWII B-17 bombers and German FW-190s increased their armaments as the war progressed. B-17 bombers increased their firepower slight but could never bring more than 5 guns to bear in any one attacking direction.
Bomber armament efforts were expended on better gun sights, to help in target tracking. FW-190 increased their firepower by an order of magnitude during the war. The key to bomber survival was staying in formation taking advantage of the mutual protection provided. To match the firepower of a FW-190, a straggling Bomber would need 20 .50 caliber machine guns bearing in the fighter’s direction. This firepower parity can only come thru mutual defensive support formation flying.