Browning Model M4, 37 mm cannon

	Browning Model M4, 37 mm cannon


	The 37 mm Automatic Gun, M4, known as the T9 during development, was a 37 mm (1.46 in) autocannon designed by John Browning and used in the Bell P-39 Airacobra and P-63 Kingcobra fighters, as well as experimentally on other designs. It provided interceptors with a weapon that could shoot down any bomber with as little as one hit. It was a compact design with a relatively low muzzle velocity and rate of fire.