Monday 2 November 2015

Imperial Japanese Navy Ammunition - 100mm and 120mm Projectiles (Part 1)

 
 
 
 
Imperial Japanese Navy Ammunition
 
 
 
 
 
 
 
10cm (100mm)(3.9 inch) Complete Round (Fixed)

 
Case:
-Length: 32.25 inches
-Diameter: 6.81 inches
-Material: Brass
-Weight (Empty): No Data
 
The case is crimped tightly into a groove in the base of the projectile by a single continuous crimp.
 
Propellant: 20 DE2(?) (Type 93 Mk 2 propellant) 12.7 lbs (5.74kg)
 
Documentary evidence and relationship to other known propellants indicates that this propellant is a double base powder in the form of flat strips.
 
Primer: Mk 2 case percussion primer, Model 4
 
Weapons used in:
-Type 98 10cm/50 dual-purpose gun
-Type 98 10cm/85 dual-purpose, twin
 
The latter is a modern gun, paired in a twin power-driven mount designed especially for anti-aircraft aboard ships.  It has been found ashore, unaltered in the characteristic gun-house mount used aboard ship.
 
Special features of this gun and mount are horizontally opposed sliding breech blocks, full power drive, and automatic fuze setting accomplished as the loading tray moves the round into position to be rammed.  The arrangement for loading and fuze setting, and the general plan of the mount corresponds closely to that of the Type 89 12.7cm/40 twin mount.
 
 
 
 
10cm (100mm)(3.9 inch) High-Explosive Projectile
 
  
Assembled Round:
-Weight of complete round: 62.75 lbs
-Length of complete round, with Type 98 fuze: 46 inches 
 
Projectile:
-Weight of filled projectile (without fuze): 28.19 lbs
-Weight of projectile, empty: 25.06 lbs
Weight stamped on rotating band (sample): 10.88kg (varies with individual projectiles)
-Length of projectile (without fuze): 12.63 inches
-Diameter at bourrelet: 3.94 inches
-Distance from base to rotating band: 2.69 inches
-Width of rotating band: 1.75 inches
-Radius of ogive: No Data
 
Filling: TNT (Type 92 explosive): 3.13 lbs
 
The charge consists of a single block of explosive cast and sealed in a waxed paper container, encased in a heavy cotton flannel bag and sealed in the projectile with paraffin.
 
Fuzing:
-Type 98 mechanical time fuze (45 seconds)
-Type 88 point detonating fuzes
 
Weapons use in:
-Type 98 10cm/65 dual-purpose gun
-Type 98 10cm/50 dual-purpose gun
   
 
 
 
12cm/Short (120mm)(4.7inch) Complete Round (Fixed)

 
Case:
-Length: 11.19 inches
-Diameter of base: 5.81 inches
-Material: Brass or steel
 
The case is crimped tightly into a groove in the base of the projectile by a single continuous crimp.
 
Propellant: 9 C3 (Type 89 propellant): 1.1 lb (0.5kg)
 
Unperforated cylindrical sticks, approximately 0.9mm by 6-7 inches, amber-coloured double-base powder.
 
The propellant sticks are enclosed in a compartmented bag of heavy brownish silk.
 
Primer: Mk 1 case percussion primer, Model 4
 
Weapon used in: Short 12cm gun
This is a short-barreled (12 caliber) gun of a pedestal mount designed originally for use on the light decks of merchant ships.  The purpose of this weapon is to deliver a relatively heavy projectile at a limited range for anti-submarine attack and to throw up low level anti-aircraft barrage.
  
This gun fires fixed ammunition; the breech block is of the interrupted thread type.  This gun is the lighter-caliber counterpart of the short 20cm gun, which has been found mounted ashore.
  
  
  
  
12cm/Short (120mm)(4.7inch) High-Explosive
 
Assembled Round:
-Weight of complete round: No Data
-Length of complete round (with Type 0 fuze): 24.8 inches
 
Projectile:
-Weight of filled projectile (without fuze): 26 lbs
-Weight of projectile, empty: 20.5 lbs
-Weight stamped on rotating band (sample): 9.34kg (varies with individual projectiles)
 
Dimensions:
-Length of projectile (without fuze): 12.6 inches
-Diameter at bourrelet: 4.7 inches (119.5mm)
-Distance from base to rotating band: 1.5 inches
-Width of rotating band: 1 inch
-Radius of ogive: No Data
 
Filling:
-Trinitroanisole (Type 91 explosive): 5.5 lbs
 
The charge consists of a single block of explosive cast and sealed in a waxed paper container, encased in a heavy cotton flannel bag and sealed in the projectile with paraffin.
 
Fuzing:
-Type 0 mechanical time fuze (red-nosed) for AA use
-Type 88 Model 4 point detonating fuze
 
Weapons used in: Short 12cm gun
 
Remarks:
The extremely thing wall of the projectile is possible only by virtue of the low muzzle velocity of the howitzer-like weapon.  The high charge/weight ratio is intended for effectiveness in use as an under-water charge against submarines, though the projectile may also be time-fuzed for anti-aircraft use.
 
  
 
 
12cm (120mm)(4.7inch) Complete Round (Semi-fixed)

 
Case:
-Length: 21.63 inches
-Diameter of base: 6.38 inches
-Material: Brass
-Weight (empty): 11.13 lbs
 
Propellant: 30 DC (Type 13 propellant): 11.88 lbs (5.4kg)
 
Unperforated cylindrical sticks, approximately 3mm by 19.4 inches (long sticks) or 6.4 inches (short sticks), amber-coloured double-base powder.  The propellant sticks are enclosed in a bag of heavy brownish silk.
 
Primer: Mk 1 case percussion primer, Model 4
 
Weapons used in:
-Type 3-year 12cm/45 gun (low angle)
 
This is a pedestal-mounted deck gun characterized by having three recoil cylinders, all mounted below the tube.  An interrupted thread breech block is hinged to swing horizontally to the right.  This gun has been found both with and without an attached splinter shield.
 
-British Type 12cm/40 gun (low angle)
 
This gun is characterized by having no recoil cylinders above the tube.  An interrupted thread breech block is hinged to swing horizontally to the right.  Guns of original British manufacture as well as Japanese-made copies have been found in Japanese island defenses.
 
The following gun is known to use semi-fixed ammunition strongly resembling that for the two guns listed above, but exact size and description of propellant case is not available.
 
Type 11-year 12cm/45 gun (low angle)
 
This gun is unique in having two recoil cylinders above the tube and one below.  The breech block is the horizontal sliding type.
 
 
 
  
12cm (120mm)(4.7inch) High-Explosive (Ordinary Mk 3)
 
-Weight of filled projectile (without fuze): 44.75 lbs
-Weight of projectile, empty: 41.14 lbs
-Weight stamped on rotating band (sample): 18.52kg (varies with individual projectiles)
-Length of projectile (without fuze): 15.95 inches
-Diameter at bourrelet: 4.6 inches (119mm)
-Distance from base to rotating band: 0.78 inch
-Width of rotating band: 1.95 inches
-Radius of ogive: 4 cal
 
Filling: Cast Picric Acid (Shimose): 3.61 lbs
 
The charge consists of two blocks of explosive cast and sealed in a waxed paper container, encased in a heavy cotton-flannel bag and sealed in the projectile with paraffin.
 
Fuzing:  Type 5-year point detonating fuze
 
Weapons used in:
-British Type 12cm/40 gun (low angle)
-Type 3-year 12cm/45 gun (low angle)
-Type 11-year 12cm/45 gun (low angle)
 
 
 
  
12cm (120mm)(4.7inch) High-Explosive (Ordinary Mk 3 Mod 1)

 
-Weight of filled projectile (without fuze): 44.75 lbs
-Weight of projectile, empty: 41.14 lbs
-Weight stamped on rotating band (sample): 18.52kg (Varies with individual projectiles)
-Length of projectile (without fuze or adapter): 14.1 inches
-Diameter at bourrelet: 4.7 inches (119.5mm)
-Distance from base to rotating band: 0.78 inch
-Width of rotating band: 1.95 inches
-Radius of Ogive: 4 cal
 
Filling: Cast picric acid (shimose) 3.61 lbs
 
The charge consists of two blocks of explosive cast and sealed in a waxed paper container, encased in a heavy cotton flannel bag and sealed in the projectile with paraffin.
 
Fuzing:
A. With adapter: Type 5-year point detonating fuze
B. Without adapter: Type 88 point detonating fuze
 
This projectile cannot be fuzed with standard mechanical fuzes for AA use because it will not accommodate the auxiliary gaine used with these fuzes.
 
Weapons used in:
-British Type 12cm/40 gun (low angle)
-Type 3-year 12cm/45 gun (low angle)
-Type 11-year 12cm/45 gun (low angle)
 
 
 
 
12cm (120mm)(4.7inch) High Explosive (Ordinary Mk 4)
 
 
 
-Weight of projectile, filled (without fuze): No Data
-Weight of projetile, empty: 39.06 lbs
-Weight stamped on rotating band (sample): 17.62 kg (varies with individual projectile)
-Length of projectile (without fuze): 13.94 inches
-Diameter at bourrelet: 4.7 inches (119.5mm)
-Distance from base to rotating band: 1.19 inches
-Width of rotating band: 1.25 inches
-Radius of ogive: No Data
 
Filling: Picric acid (shimose): No Data
 
Fuzing:
-Type 91 mechanical time fuze
-Type 88 point detonating fuze
 
Weapons used in:
-British Type 12cm gun (low angle)
-Type 3-year 12cm/45 gun (low angle)
 
 
 
 
12cm (120mm)(4.7inch) Common Projectile
 
 
-Weight of filled projectile (with fuze): 45.12 lbs
-Weight of empty projectile: 40.56 lbs
-Length of projectile: 16.39 inches
-Diameter at bourrelet: 4.7 inches (119.5mm)
-Distance from base to rotating band: 1.19 inches
-Width of rotating band: 1.25 inches
-Radius of ogive: No Data
 
Filling: Picric acid (Shimose): No Data
 
Fuzing: Type 3-year Mk 1 base fuze
 
Weapons used in:
-British Type 12cm/40 gun (low angle)
-Type 3-year 12cm/45 gun (low angle)
-Type 11-year 12cm/45 gun (low angle)
 
 
 
 
12cm (120mm)(4.7inch) Illuminating Projectile
 
 
-Weight of filled projectile: 44 lbs
-Weight of empty projectile: No Data
-Weight stamped on rotating band: No Data
-Length of projectile (without fuze): 13 and 13/16 inches
-Diameter at bourrelet: 4 and 11/16 inches (119mm)
-Distance from base to rotating band: No Data
-Width of rotating band: 1 and 15/16 inches
-Radius of ogive: No Data
 
Filling: Expelling charge (black powder): 0.5 oz
 
Illuminant:  There are 10 pyrotechnic cylinders arranged in two layers of 5 cylinders each.  A cylinder is formed of a tough waxed cardboard tube containing a silver pyrotechnic mixture in thee center and a reddish-brown pyrotechnic mixture in either end.
 
Weight (each cylinder): 5.4 oz
 
Analysis of illuminant:
-Barium nitrate: 35.6%
-Potassium nitrate: 10.4%
-Magnesium: 38%
-Wax: 13.9%
-Carbon: 0.8%
-Sulphur: 1.3%
 
Analysis of first fire compound:
-Potassium nitrate: 63.2%
-Iron oxide: 3.8%
-Aluminium oxide: 1.1%
-Sulphur: 8.2%
-Wax: 5.5%
-Glass: 6.1%
-Carbon: 12.1%
 
Cylinder metal frame:
This frame fills the cavity of the projectile and is positioned by studs.  There are three metal discs attached to a central spindle which provides a method of functioning and serves to support the pyrotechnic increments.  Arranged about the circumference of this frame are two layers of five steel wedges which position the pyrotechnic increments within the frame.
 
Fuzing: 30-second time fuze
 
Weapons used in:
-Type 11-year 12cm/45
-Type 3-year 12cm/45
 
Operation:  When the fuze functions, the flash from the black powder magazine ignites a small black powder charge in the nose of the projectile, which in turn ignites the powder trains in the central spindle.  The flash from this train ignites the powder trains in the three discs and thus the ten increments and the ejecting charge.  As the cylinder is blown from the case, it shears the studs and forces the nose and body of the projectile apart.
 
 
 
 
Next Time:  120mm Projectiles (Part 2)

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