Japan
12 cm/12 (4.7") Short Gun
Updated 27 May 2012
Similar in concept to the 20 cm/12 (8") Short Gun, this weapon was intended for lighter merchant vessels.  Also used in coastal defense batteries.  Monobloc construction with a screw breech.

Actual bore size was 12.0 cm (4.724").
WNJAP_47-12_Short_pic.jpg

12 cm/12 (4.7") gun in coastal defense battery
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Gun Characteristics
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Designation 12 cm/12 (4.7") Short Gun
Ship Class Used On Merchant vessels under 5,000 grt
Date Of Design 1941
Date In Service about 1942
Gun Weight 481 lbs. (218 kg)
Gun Length oa 59.5 in (1.510 m)
Bore Length 56.7 in (1.440 m)
Rifling Length 44.4 in (1.127 m)
Grooves (24) 0.039 in deep x 0.465 in (1.0 mm x 11.78 mm)
Lands 0.155 in (3.93 mm)
Twist Increasing RH 1 in 30 to 1 in 13
Chamber Volume 183 in3 (3.0 dm3)
Rate Of Fire 8 rounds per minute
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Ammunition
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Type Separate or fixed
Projectile Types and Weights HE - 28.7 lbs. (213 kg)
Bursting Charge 5.6 lbs. (2.5 kg)
Projectile Length 13.2 in (33.6 cm)
Propellant Charge 1.08 lbs. (0.49 kg)
Muzzle Velocity 951 fps (290 mps)
Working Pressure 4.4 tons/in2 (700 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
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Range
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Elevation 45.0 lbs. (20.41 kg) HE Shell
Maximum range 5,800 yards (5,300 m)
Ceiling @ 75 degrees 9,190 feet (2,800 m)
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Mount / Turret Data
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Designation Single Mounts
Weight  1.86 tons (1.89 mt)
Elevation -15 / +75 degrees
Elevation Rate 12 to 13 degrees per second (manual operation)
Train 360 degrees (?)
Train Rate 12 to 13 degrees per second (manual operation)
Gun recoil N/A
Loading Angle Any
Note:  Hand loading was possible at any elevation, but ammunition supply was strictly by hand.
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Data from
"Naval Weapons of World War Two" by John Campbell
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US Naval Technical Mission to Japan report O-54(N):  Japanese Naval Guns
Page History

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