I think that it was the Lockheed P-38 Lightning that introduced this 'world of hurt' in the nose. But it was in fact four .50 caliber machine guns and two twenty millimeter cannons on the business end of things! All this armament was deployed on a twin engine airframe with long range, awesome rate of climb and great maneuverability that made for an excellent fighter package.

[Linked Image from 49fastback.com]