Short-barreled 3.0" (7.62 cm) used on submarines and gun boats. Later used with AA mountings on other ships during World War I.

Redesignated in centimeters on 5 October 1917.

Although the Japanese designation was "8 cm," the actual bore diameter of all these weapons was 7.62 cm (3.0"). Bore length was actually either 23.37 calibers or 23.07 calibers.

Gun Characteristics

Designation 3"/40 (7.62 cm) Short Guns
8 cm/40 (3") Short Guns
Ship Class Used On Small ships and submarines
Date Of Design 1902 (?)
Date In Service 1903 (?)
Gun Weight Model Type VI and VIII: 715 lbs. (316 kg)
Others: N/A
Gun Length oa Model Type VI and VIII: 73.7 in. (1.872 m)
Bore Length Model Type I and IV: 69.3 in (1.758 m)
Model Type VI and VIII: 70.1 in (1.780 m)
Rifling Length Model Type I and IV: 58.4 in (1.482 m)
Model Type VI and VIII: 59.9 in (1.504 m)
Grooves Model Type I and IV: (16) 0.024 in deep (0.6 mm deep)
Model Type VI and VIII: (24) 0.039 in deep x 0.241 (1.0 mm deep x 6.12 mm)
Lands N/A
Twist Model Type I: Uniform RH 1 in 25.59
Model Type VI and VIII: Uniform RH 1 in 28
Chamber Volume 72.6 in3 (1.19 dm3)
Rate Of Fire about 15 rounds per minute


Type Fixed
Weight of Complete Round N/A
Projectile Types and Weights Common 12.5 lbs. (5.67 kg)
Common 12.8 lbs (5.79 kg)
Bursting Charge N/A
Projectile Length N/A
Propellant Charge N/A
Muzzle Velocity 1,476 - 1,493 fps (450 - 455 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A

Mount/Turret Data

Designation Single mounts
Weight about 3.3 tons (3.35 mt)
Elevation N/A
Elevation Rate Manually operated, only
Train 360 degrees
Train Rate Manually operated, only
Gun recoil N/A


"Naval Weapons of World War Two" by John Campbell
US Naval Technical Mission to Japan report O-54(N): Japanese Naval Guns

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