Mustang left and right (Rollover) frontal views, armed with six 50-caliber (12.7mm) heavy machine guns, two racks for 500-lb bombs or 100-gallon drop tanks. External fuel tanks significantly extended P-51 range to 850 miles, covering every target point in Western Europe. Although these tanks comprised flight stability to a degree, they were dropped to regain full agility when enemy fighters were engaged. Drop Tank - en.wikipedia.org/wiki/Drop_tank

Mustang outperformed many of its German counterparts (ex. Messerschmidt Bf-109 and Focke-Wulf Fw-190) since latter was usually heavily laden with ammunition and aerial rockets for battle against US bomber forces. Only arrival of Messerschmidt Me-262 Jet fighters in late-1944 did US bomber formations suffer consistent losses to such an extend that Allied bombing effort shifted from industrial power centers to jet manufacturing plants. Messerschmitt Me 262 - en.wikipedia.org/wiki/Me-262

Mustang's streamline fuselage design is argued by some as the sleekest and robust WW2 Allied fighter (hence, its numerous depictions in war movies), but others argue that P-47 Thunderbolt ground-attack fighters and F4U Corsair naval interceptors can command the same attention. M2 .50 Caliber [12.7mm] Machine Gun "Ma Duce" - www.fas.org/man/dod-101/sys/land/m2-50cal.htm

50-caliber machine gun was designed by John Moses Browning, his gun design influenced nearly a century of American gun development. From a historical-sociology impact, firearms can trace their origins to 16th-century Europe, but it was American gun mechanic and ammunition ingenuity - invention - insights in the past 200 years which propelled firearms as a dependable mainstay of modern arms. It is also this reason why American society in general possess a special relationship with the gun. John Browning - en.wikipedia.org/wiki/John_Browning