Japan
12.7 cm/40 (5") Type 88
12.7 cm/40 (5") Type 89
Updated 05 March 2008
The Type 88 was used only on two submarines in single mountings.  The very similar Type 89 was an AAA weapon used in twin mountings on most World War II ships cruiser size and larger as well as on small destroyers.  The Type 89 was also used to replace many of the 12 cm/45 (4.7") AA guns on older cruisers.

The Type 89 was a good AAA weapon with a fast rate of fire and excellent elevation and training speeds on the later Mods.  Its primary shortcoming was a relatively low muzzle velocity and thus a short range and low AA ceiling.

These weapons were of simple construction with autofretted monobloc barrels and breech rings and used horizontal sliding breech-blocks.  Total production of Type 89 guns amounted to 1,306 guns, with 836 being manufactured between 1941 and 1945.  Of these, 362 were mounted ashore, including 96 in the Yokosuka area and 54 in the Kure area.

Unless otherwise specified, the data that follows is for the Type 89.
WNJAP_5-40_t89_Mushasi_pic.jpg

12.7 cm (5") twin mount on battleship IJN Musashi
Detail from U.S. Naval Historical Center Photograph # NH 73091
WNJAP_5-40_t89_Haguro_pic.jpg

12.7 cm (5") twin mount on unidentified cruiser about 1932
In the background is IJN Haguro
Detail from U.S. Naval Historical Center Photograph # NH 88373
WNJAP_5-40_t89_Nagato_pic.jpg

12.7 cm (5") gun mount on IJN Nagato
WNJAP_5-40_t89_Destroyer_pic.jpg

Tachibana class escort showing single bow and twin stern 12.7 cm/40 mounts
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Gun Characteristics
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Designation 12.7 cm/40 (5") Type 88 (Model 1928)
12.7 cm/40 (5") Type 89 (Model 1929)
Ship Class Used On Type 88:  Submarines I.5 and I.6

Type 89:  Almost all Japanese ships cruiser size and larger, Matsu and Tachibana class escorts
Date Of Design 1928 / 1929
Date In Service 1932
Gun Weight 3.05 tons (3.1 mt)
Gun Length oa 208 in (5.284 m)
Bore Length 200 in (5.080 m)
Rifling Length 175 in (4.450 m)
Grooves (36) 0.060 in deep x 0.261 in (1.52 mm x 6.63 mm)
Lands 0.175 in (4.45 mm)
Twist Uniform RH 1 in 28
Chamber Volume 549 in3 (9.0 dm3)
Rate Of Fire Type 88:  8 rounds per minute

Type 89:  8 - 14 rounds per minute
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Ammunition
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Type Fixed
Weight of Complete Round Common Type 0 HE - 75.7 lbs. (34.32 kg)
Common Type 3 IS - 77.2 lbs. (35 kg)
Illum - 75.7 lbs. (34.32 kg)
Projectile Types and Weights
(see Note 1)		 Common Type 0 HE - 51.7 lbs. (23.45 kg)
Common Type 3 IS - 50.7 lbs. (23.0 kg)
ASW - 46.2 lbs. (20.9 kg)
Illum - 51.7 lbs. (23.45 kg)
Bursting Charge Common Type 0 HE - 4.2 lbs. (1.88 kg)
ASW - 8.78 lbs. (4.0 kg)
Projectile Length Common Type 0 HE - 17.2 in (43.7 cm)
Common Type 3 IS - 17.2 in (43.7 cm)
ASW - 17.2 in (43.7 cm)
Complete Round Length 38.2 in (97.1 cm)
Cartridge Case Type, Size and Empty Weight Brass, 127 x 583 mm, about 15.23 lbs. (6.9 kg)
Propellant Charge 8.77 lbs. (3.98 kg) 21 DC
Cartridge - 26.3 lbs. (12 kg)
Muzzle Velocity Common Type 0 HE - 2,360 - 2,379 fps (700 - 725 mps)
Common Type 3 IS - 2,360 - 2,379 fps (700 - 725 mps)
ASW - 820 fps (250 mps)
Illum - 2,362 fps (720 mps)
Working Pressure 16 tons/in2 (2,500 kg/cm2)
Approximate Barrel Life 800 - 1500 rounds
Ammunition stowage per gun Yamato class:  300 rounds
Cruisers with 4 guns:  250 rounds
Cruisers with 8 guns:  200 rounds
Others:  N/A
Notes:

1) IS is my abbreviation for the incendiary shrapnel round (sankaidan) intended for AA use.

2) 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 9.85 in (25 cm) plate of Ducol Steel (roughly equivalent to USN HTS) at a depth of 26 feet (8 meters).  Range for this performance is not given.  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 0.985 in (2.5 cm).  ASW may have been issued only to escorts.

3) Illumination rounds were rated at 680,000 candle power and had a maximum range of 15,910 yards (14,550 m) and an effective range of 8,750 yards (8,000 m).

4) Common Type 0 HE was considered to have an 62.7 foot (18.8 m) effective radius of destruction.
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Range
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Elevation With 50.7 lbs. (23 kg) IS Shell
Range @ 45 degrees 16,185 yards (14,800 m)
AA Ceiling @ 75 degrees 30,840 feet (9,400 m)
Elevation With 46.2 lbs. (22.0 kg) ASW Shell
Range @ 40 degrees 4,700 yards (4,300 m)
Note:  Minimum range of ASW shell is given as 875 yards (800 m).  Ranges less than this tended to ricochet.
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Mount / Turret Data
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Designation Type 88 Single Mounting
   I.5 and I.6 (1):  A1

Type 89 Twin Mounts
   Aoba (2), Furataka (2), Takao (4), Atago (4) and Maya (4):  A1
   Myoko (4), Mogami (4) and Tone (4):  A1 Mod 1
   Kaga (8), Ryujo (4), Shokaku (8) and Hiryu (6):  A1 Mod 2
   Yamato (6):  A1 Mod 3
   Matsu (1) and Tachibana (1):  B1
   Shoho (4), Hiyo (6), Ryuho (4), Chiyoda (4), Kaiyo (4), Shinyo (4), Shinano (8), Unryu (6):  N/A

Type 89 Single Mount
   Matsu (1) and Tachibana (1):  B1 Mod 4
Weight  Type 88
   8.7 tons (8.8 mt)

Type 89:
   A1:  20 tons (20.3 mt)
   A1 Mod 1:  24 tons (24.5 mt)
   A1 Mod 2:  N/A
   A1 Mod 3:  28.5 tons (29 mt)
   B1:  N/A
   B1 Mod 4:  N/A
Elevation Type 88:  - 7 / +75 degrees

Type 89:  -7 / +90 degrees (one source says -8 / +85 degrees)
Elevation Rate Type 88
   Manual operation, only.

Type 89
   A1 (all):  12 degrees per second
   B1:  16 degrees per second
Train Amidships Mounts:  About -70 / +70 degrees

Bow and Stern Mounts:  About -150 / +150 degrees
Train Rate Type 88
   Manual operation, only.

Type 89
   A1 (all):  6 to 7 degrees per second
   B1:  16 degrees per second
Gun recoil 17.75 in (45.0 cm)
Loading Angle Any
Notes:

1) The A1 mount was unshielded.  The A1 Mod 1 added a shield, while the shield for the A1 Mod 2 had a slightly different shape and the A1 Mod 3 had a thicker shield.  The B1 had no shield but did have a more powerful electric training motor.

2) The battleships Yamato and Musashi had their two amidships 15.5 cm/60 (6.1") triple mountings removed in 1944.  Yamato had six twin 12.7 cm/40 (5") mountings installed in their place, giving her a total of twenty-four 12.7 cm/40 (5") guns.  Musashi was also to receive six additional twin mountings, but these were not available prior to her loss.

3) Ramming was via a spring-powered mechanism that was cocked by the recoil force when the gun fired.  Fuze-setting machines were fixed to the breech faces of the guns.  Most ships had one or two hoists per twin mounting.
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Data from
"Naval Weapons of World War Two" by John Campbell
"Battleships:  Axis and Neutral Battleships in World War II" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
"The Japanese Ships of the Pacific War" by The Koku-Fan
"Japanese Cruisers of the Pacific War" by Eric Lacroix and Linton Wells II
"Anatomy of the Ship:  The Heavy Cruiser Takao" by Janusz Skulksi
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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-47(N)-1:  Japanese Naval Guns and Mounts-Article 1, Mounts Under 18"