The 25 mm Type 96 was widely used throughout the Japanese Navy with about 33,000 guns being produced. The Japanese considered this gun to be an excellent weapon, but it did not compare well to either the Bofors 40 mm or the Oerlikon 20 mm weapons used by the Allies. The magazines for the Type 96 held only 15 rounds, so frequent stoppages for change outs were required. By 1945, these weapons fired projectiles too light and too short ranged to effectively engage the heavier and faster US aircraft then in service.
The Japanese were the only major navy of World War II not to develop and deploy any AA machine guns larger than 25 mm (1").
Used a forged monobloc barrel and the automatics were gas-operated.
Triple 25 mm at Guadalcanal in 1942
Twin 25 mm
Single 25 mm gun on Guam in October 1944
Twin 25 mm gun on Guam in October 1944
|Designation||25 mm/60 (1") Type 96 (Model 1936)|
|Ship Class Used On||Almost all warships of World War II|
|Date Of Design||1935 (In Japan)|
|Date In Service||1936|
|Gun Weight||253.5 lbs. (115 kg) not including magazine|
|Gun Length oa||90.4 in. (2.296 m) [one source says 96.5 in (2.420 m)]|
|Barrel Length||59.1 in (1.500 m)|
|Rifling Length||53.2 in. (1.350 m)|
|Grooves||(12) 0.0098 in deep x 0.141 in (0.25 mm x 3.58 mm)|
|Lands||0.117 in (2.96 mm)|
|Twist||Uniform 1 in 25.2|
|Rate Of Fire||Cyclic: 220 - 260 rounds per minute
Effective: 110 - 120 rounds per minute
1) Cartridge ejection was a problem at high elevations and stoppages were frequent.
2) The barrel was secured to the breech mechanism by screw threads, but the gas cylinder connections made changeouts difficult. Two men using a hammer and a spanner wrench could complete a changeout in about five minutes.
|Weight of Complete Round||All types about 1.5 lbs. (0.68 kg)|
|Projectile Types and Weights
(see Note 1)
|AP - 0.57 lbs. (0.26 kg)
Common - 0.55 lbs. (0.24 kg)
Incendiary Common - 0.55 lbs. (0.25 kg)
Tracer - 0.55 lbs. (0.25 kg)
|Bursting Charge||AP and Tracer - None
Common - 0.02 lbs. (0.01 kg)
Incendiary Common - 0.02 lbs. (0.01 kg)
|Projectile Length||AP - 4.0 in (10.2 cm)
Common - 4.4 in (11.2 cm)
Incendiary Common - 4.3 in (11.0 cm)
|Propellant Charge||3.60 - 3.88 oz. (102 - 110 gm) Type 1 No. 2 (K3)|
|Muzzle Velocity||2,953 fps (900 mps)|
|Working Pressure||17.1 tons/in2 (2,700 kg/cm2)|
|Approximate Barrel Life||12,000 rounds|
|Ammunition stowage per gun||2,000 rounds|
1) Projectile data from "Japanese Cruisers of the Pacific War." "Naval Weapons of World War Two" says that the AP round weighed 0.62 lbs. (0.28 kg).
2) Normal allocation was one tracer in every five rounds.
3) Shell Colors
|Elevation||With 0.55 lbs. (0.25 kg) HE Shell|
|Range @ 45 degrees||7,439 yards (6,800 m)|
|Range @ 50 degrees||8,200 yards (7,500 m)|
|AA Ceiling @ 85 degrees||Effective: 9,843 feet (3,000 m)
Maximum: 18,040 feet (5,500 m)
|Note: The sources listed below disagree as to the ranges and AA ceiling for this weapon. I have chosen to use those given in "Japanese Cruisers of the Pacific War."|
|Designation||Single, Twin and Triple Mounts|
|Weight||Single: 1,731 lbs. (785 kg)
Twin: 2,425 lbs. (1,100 kg)
Triple: 3,970 lbs. (1,800 kg)
|Elevation||-10 / +85 degrees|
|Elevation Rate||Most were manually operated
Some triples had Ward-Leonard RPC: 12 degrees per second
|Train Rate||Most were manually operated
Some triples had Ward-Leonard RPC: 18 degrees per second
|Gun recoil||4.33 in (11 cm)|
1) Triple manually controlled mountings had nine crewmembers (1 pointer, 1 trainer, 1 sight setter and 2 loaders per gun). Twin mountings were similarly manned (seven crewmembers total). Single mountings had three crewmembers (1 gun layer, 1 loader and 1 gun captain).
2) About 20,000 mountings of all types were produced.
3) Ship board installations according to
4) According to US Naval Technical Mission
to Japan report O-47(N)-2, the Japanese saw the following deficiencies
in these mountings in decreasing order of seriousness:
5) Apparently, all magazines had to be loaded by hand as no specialized loading equipment was ever developed.
Ichinohe Takao 25
3 December 2008 - Benchmark
04 March 2009 - Redid picture of twin gun on Guam