Japan
3"/40 (7.62 cm) 3rd Year Type
8 cm/40 (3") 3rd Year Type
8 cm/40 (3") 11th Year Type
8 cm/40 (3") Type 88

Updated 27 May 2012

3rd Year and 11th Year Types were used on many smaller ships and cruisers built prior to World War II while the Type 88 was used on submarines.

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").
WNJAP_3-40_3ns_pic.jpg

8 cm/40 (3") 3rd Year Type
Picture courtesy of Taku Saito and from Museum Trip
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Gun Characteristics
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Designation 3"/40 (7.62 cm) 3rd Year Type (Model 1914)
8 cm/40 (3") 3rd Year Type (Model 1914)
8 cm/40 (3") 11th Year Type (Model 1922)
8 cm/40 (3") Type 88 (Model 1928)
Ship Class Used On Furutaka and Aoba (as built)
Small ships and submarines
Date Of Design 1914, 1922 and 1928
Date In Service 1916, 1926 and 1932
Gun Weight 1,323 lbs. (600 kg)
Gun Length oa 126.1 in. (3.203 m)
Bore Length 120.0 in (3.048 m)
Rifling Length
(see Note)		 All except Model Type IV:  102.7 in. (2.608 m)
Model Type IV:  103.2 in (2.623 m)
Grooves Barrel Model Types I and II:  (16) 0.39 in deep x 0.366 in (1.00 mm x 9.300 mm)
Barrel Model Types III, IV and VII:  (24) 0.39 in deep x 0.232 in (1.00 mm x 5.905 mm)
Lands 0.160 in (4.07 mm)
Twist Uniform RH 1 in 28
Chamber Volume 128 in3 (2.1 dm3)
Rate Of Fire 13 to 20 rounds per minute
Note:  The Model Type IV barrel had a slightly longer chamber length, hence the difference in rifling length.  The Chamber Volume was the same as in the other Model Types.
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Ammunition
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Type Fixed
Weight of Complete Round Common Type 0 HE - 20.4 lbs. (9.25 kg)
ASW - N/A
Projectile Types and Weights Common Type 0 HE - 13.2 lbs. (5.99 kg)
ASW - 11.7 lbs. (5.3 kg)
Bursting Charge Common Type 0 HE - 1.06 lbs (0.48 kg)
ASW - 1.5 lbs. (0.67 kg)
Projectile Length Common Type 0 HE - 11.1 in (28.2 cm)
ASW - 11.3 in (28.5 cm)
Propellant Charge Common Type 0 - 2.0 lbs. (0.9 kg) 20 C3
ASW - N/A
Muzzle Velocity Common - 2,231 to 2,247 fps (680 to 685 mps)
ASW - 820 fps (250 mps)
Working Pressure 14.5 tons/in2 (2,250 kg/cm2)
Approximate Barrel Life 1,200 - 2,000 rounds
Ammunition stowage per gun N/A
Note:  The flat-nosed ASW projectile was issued in 1943 following extensive testing.  This is listed in US Naval Technical Mission to Japan report O-19 as being able to penetrate a 4.53 in (11.5 cm) plate of Ducol Steel (roughly equivalent to USN HTS) at a depth of 26 feet (8 meters).  However, based upon other errors in this document, I would believe this to be an error in metric to english unit conversion and that the actual performance would more likely be 0.453 in (1.15 cm).  Range for this performance is not given.
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Range
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Elevation With 13.2 lbs. (5.99 kg) HE Shell
Range @ 45 degrees 11,800 yards (10,800 m)
AA Ceiling @ 75 degrees 23,600 feet (7,200 m)
Elevation With 11.7 lbs. (5.3 kg) ASW Shell
Range @ 40 degrees 3,500 yards (3,200 m)
Note:  Minimum range of ASW shell is given as 766 yards (700 m).  Ranges less than this tended to ricochet.
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Mount / Turret Data
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Designation Single mounts
Weight  about 3.3 tons (3.35 mt)
Elevation  -7 / +75 degrees 
Elevation Rate Manually operated, only
7 - 10 degrees per second
Train 360 degrees
Train Rate Manually operated, only
10 - 11 degrees per second
Gun recoil N/A
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Data from
"Naval Weapons of World War Two" by John Campbell
"Cruisers of World War Two" by M.J. Whitley
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US Naval Technical Mission to Japan report O-19:  Japanese Projectiles General Types
US Naval Technical Mission to Japan report O-54(N):  Japanese Naval Guns
Page History

23 November 2006 - Benchmark
27 May 2012 - Updated to latest template