i just read a piece (a piece o' kr@p, i think) that indicated P-38s flown out of Port Morsby by 80th squadon of the 8th fighter group in the 5th air force were armed with 4 x 0.50 + 2 x 20mm. i dont believe it, in fact i cannot recall ever hearing of a Lightning aand anyway other than 4 x 0.50 + 1 x 20mm...anyone know anything about this?
In the spring of 1939, the Air Corps issued a request for an advanced twin-engine interceptor, to be derived from an existing type and fitted with advanced high-performance engines. Lockheed responded to the request with the "Model 222", which was much like a P-38 except that it had a pressurized cabin and was to be powered by 24-cylinder inline Pratt & Whitney X-1800-SA2-G engines, which were in development and were expected to provide over 2,000 horsepower. The Model 222 was to be armed with four 12.7-millimeter and two 20-millimeter guns, and a P-38G was modified to test this armament fit.
The XP-58 started life in the spring of 1940 as an advanced escort fighter version of the P-38, with the development at the request of the USAAF. Single-seat and two-seat versions were considered, with the two-seat version fitted with additional turret-mounted armament. The single-seat version was quickly abandoned, and the two-seat version went through a number of radical design changes, particularly with regards to engine fit. With the outbreak of the Pacific War in December 1941, the project was more or less put on the "back burner", with most of the staff moved to higher-priority projects. The USAAF then began to flip-flop on their requirements, redefining the XP-58 as a ground attack aircraft, then a bomber, then an interceptor, with a bewildering variety of equipment fits considered. The single XP-58 prototype finally flew on 6 June 1944.
The XP-58 was to mount four 37-millimeter fixed forward-firing cannon and two remote-control barbettes, each with two 12.7-millimeter machine guns, mounted at the rear of the crew nacelle. An alternate forward armament of two 12.7-millimeter machine guns and a 75-millimeter cannon, for breaking up bomber formations, was also considered, but in reality no armament was ever fitted. By the time the prototype flew, the USAAF had completely lost interest in the project, and the flight test program was short and indifferent. A second prototype was never completed, and the one flying example was scrapped after the war. Whether the XP-58 would have been a good idea or not, it still would have been interesting to see what would have happened if it had actually hit something with four 37-millimeter cannon!
After the war, a P-38L was experimentally fitted with armament of three 15.2-millimeter (0.60-caliber) machine guns. This sounds like a misprint, but such guns were actually developed. The 15.2-millimeter cartridge had been developed early in the war for an infantry "anti-tank rifle", a type of weapon developed by a number of nations in the 1930s when tanks were lighter, but by 1942 the idea of taking on a tank with a large-caliber rifle was somewhere between "outdated" and "suicidal". The cartridge wasn't abandoned, with the Americans designing a derivative of the German MG-151 15-millimeter machine gun around it and designating the weapon the "T17", but though 300 of these guns were built and over six million 15.2-millimeter rounds were manufactured, they never worked out all the bugs, and the T17 never saw operational service. The cartridge was "necked up" to fit 20-millimeter projectiles and became a standard US ammunition after the war. The T17-armed P-38L did not go beyond unsuccessful trials.
Another P-38L was modified after the war as a "super strafer", with eight 12.7-millimeter machine guns in the nose and a pod under each wing with two 12.7-millimeter guns, for a total of twelve. Nothing came of this fit, either.
