JPN - Type 99-2 Model 4 (20 mm kanon)

Autocannon Type 99-2 Model 4 Autocannon Type 99 Mark 2 Model 4
Original Title:
Original Name: 九九式二〇粍二号機銃四型
Dai Nihon Heiki K. K., Toykawa Naval Arsenal
Period of production:
Production Period:
Units produced:
Number of Produced:
Prototype Produced:
Prototype Built:
Use: Mitsubishi A6M Reisen, Mitsubishi A7M Reppū, Mitsubishi J2M Raiden, Kawanishi N1K Shiden
 Technical Data:
Weight: 37.8 kg83 lb
20 mm / 0.79 in
Barrel Length:
Barrel Length:
1054mm3ft 5.5in
Overall Length:
Overall Length: 1885mm4ft 4.39in
Ammunition Used:
Ammo Used:
Bullet, Penetrating (142g), Penetrating-Incendiary, Bursting-Incendiary, Bursting-Incendiary, Bursting-Incendiary with tracer, Bursting-Incendiary and Incendiary Ball, A.P. (5.009oz), A.P./I., T., H.E., H.E./T., H.E./I. I
Maximum Range:
Maximum Range:
0.8 - 1 km 0.5 - 0.6 mi
Rate of Fire:
Rate of Fire:
500 rpm 500 rpm
Rate of Attack:
Muzzle Velocity:
750 m/s 1968.5 ft/s
九式二号機銃 - Kyū-Kyū Shiki Nigō Kizyū, Kanji
This weapon was produced in parallel with the Type 99-1, and was produced in fixed mount or for mounting in motorized gun turrets. This type used a different type of cartridge and differed from the Type 99-1 by its long barrel. The weapon had a higher power output due to the higher muzzle velocity, and reciprocally, the weapon had a higher recoil. This model carried its ammunition supply in ammunition belts, which held 125-250 grenades. Cadence, despite requests from the Navy, remained low.
It was an improved copy of the Swiss Oerlikon FFL, and was introduced in Japanese naval aviation for its higher performance.02COL2]九式二号機銃 - Kyū-Kyū Shiki Nigō Kizyū, Kanji
The Type 99 Mark 2 was a heavier weapon with a stronger recoil, and was not put in use by the Imperial Japanese Navy before 1942. It was used exclusively in fixed installations, i.e., either in fighters or in power-operated turrets. The Type 99 Mark 2 Model 4 were belt-fed with 125 - 250 rounds.

The Model 2 was based on the Oerlikon FFL and came into use as airframes became large and strong enough to accommodate the bigger, more powerful gun.
René J. Francillon Ph.D., Japanese Aircraft of the Pacific War, Naval Institute Press, Annapolis Maryland, Reprinted 1990, ISBN-0-87021-313-X

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Picture of this version of the Type 99 cannon with long barrel
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