Ho-401 was a Japanese aircraft

autocannon An autocannon, automatic cannon or machine cannon is a fully automatic gun that is capable of rapid-firing large-caliber ( or more) armour-piercing, explosive or incendiary shells, as opposed to the smaller-caliber kinetic projectiles (bull ...

that saw limited, if any, use during World War II. It was a large-caliber version of the 37 mm

Ho-203 cannon Ho-203 was a Japanese autocannon that saw considerable use during World War II. It was a long-recoil automation of the Year 11 Type direct-fire infantry gun. It was fed by a 15-round closed-loop ammunition belt. It was operationally used only as ...

. The cannon was used on the ground attack aircraft,

Kawasaki Ki-102 The Kawasaki Ki-102 (Army Type 4 assault aircraft) was a Japanese warplane of World War II. It was a twin-engine, two-seat, long-range heavy fighter developed to replace the Ki-45 ''Toryu''. Three versions were planned: the Ki-102a day fighter, K ...

Specifications

*Caliber: 57 mm (2.25 in) *Ammunition: 57 x 121R (1,550 g) *Weight: 150 kg (330 lb) *Rate of fire: 80 rounds/min *Muzzle velocity: 495 m/s (1,624 ft/s)

References

The Pacific War Encyclopedia
Aircraft guns Autocannon Machine guns of Japan 57 mm artillery {{Machinegun-stub