Type 99 Mark 1 Autocannon

Go Back to Autocannon

Go Back To Weapons Home

	Weapon: Type 99 Mark 1 Autocannon Type: Autocannon Country of Origin: Japan Year Adopted: 1939 Caliber: 20x72RB Action: Blow Back Fully Automatic Overall Length (mm): 2200.0 Weight (kg): 43.00 Effective Range (m): 1000

The Japanese Type 99 Mark 1 autocannon was a 20mm aircraft-mounted weapon developed in the late 1930s for the Imperial Japanese Navy. Based on the Swiss-designed Oerlikon FF autocannon, the Type 99 Mark 1 was modified to meet the needs of Japanese aircraft, offering a balance of firepower and reliability. It was a short-recoil-operated design, firing 20x72RB ammunition from a 60-round drum magazine. Lightweight and compact, the autocannon could be installed in wing-mounted or flexible positions, making it a versatile armament choice for fighters and bombers alike.

Production of the Type 99 Mark 1 began in 1939 and continued through much of World War II, with the weapon being manufactured by several Japanese arsenals, including the Nagoya Arsenal. Though exact production figures are not well-documented, it is estimated that thousands of these autocannons were produced to equip a variety of aircraft, including the Mitsubishi A6M Zero and the Nakajima B5N bomber. Its high rate of fire and moderate muzzle velocity made it effective against lightly armored targets, such as enemy aircraft and ground vehicles, though it struggled against heavily armored aircraft later in the war.

The Type 99 Mark 1 earned notoriety for its role in early Pacific Theater campaigns, contributing to the success of Japanese air superiority during the initial stages of the war. It was, however, gradually outclassed by more advanced 20mm autocannons, including the Type 99 Mark 2, which featured higher velocity and greater range. Despite its limitations, the Type 99 Mark 1 remains a significant example of wartime aircraft weaponry, illustrating the adaptability of Japanese engineering. Today, surviving examples of the Type 99 Mark 1 are rare and valued by military historians and collectors for their connection to Japan's aerial combat legacy.