The Northrop P-61 Black Widow had a gun mounted that was designed by whom?
M2 Browning The M2 Machine Gun or Browning .50 Caliber Machine Gun is a heavy machine gun designed toward the end of World War I by John Browning. Its design is similar to Browning's earlier M1919 Browning machine gun, which was chambered for the .30-06 cartridge. The M2 uses the much larger and much more powerful .50 BMG cartridge, which was developed alongside and takes its name from the gun itself (BMG standing for "Browning Machine Gun"). It has been referred to as "Ma Deuce", in reference to its M2 nomenclature. The design has had many specific designations; the official designation for the current infantry type is Browning Machine Gun, Cal. .50, M2, HB, Flexible. It is effective against infantry, unarmored or lightly armored vehicles and boats, light fortifications and low-flying aircraft. The M2 has been produced longer than any other machine gun.
Shpitalny Sh-37 The Shpitalny Sh-37 (Russian: Шпитальный - Ш-37 ) was the first indigenous Soviet 37 mm aircraft cannon, designed by Boris Shpitalniy at OKB-15. The gun saw limited production and was installed in few aircraft before being replaced by the competing Nudelman-Suranov NS-37 designed at OKB-16. It was installed on a military-trial basis on two short series of aircraft. Installed to fire through the hollow, gear-driven propeller shaft and fastened to the engine block of the Yak-7-37 it was known as MPSh-37, where "MP" stands for "motornaya pushka", similar to the German "Motorkanone" term for the same mount type. As installed in the underwing gun pods of the Il-2 it was known as ShFK-37 (Russian: ШФК-37 - Шпитальный фюзеляжно-крыльевая калибра 37 мм ).