40 cm/45 Type 94 naval gun

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40 cm/45 Type 94
Yamato battleship under construction.jpg
A Type 94 Naval Gun being calibrated on Yamato during construction
Type Naval gun
Place of origin Empire of Japan
Service history
In service 1940–1945
Used by Imperial Japanese Navy
Wars World War II
Weight 147.3 tonnes
Length OA 21.13 m (69 ft 4 in) L/46
Diameter 46 cm (18 in)

Shell AP Type 91: 1,460 kg (3,218.7 lb)
HE Type 0: 1,360 kg (2,998.3 lb)
AA Type 0: 1,360 kg (2,998.3 lb)
Calibre 460 mm (18.1 in)
Elevation +45/-5 degrees. 10°/s
Traverse 300°, 2°/s
Rate of fire 1.5 - 2 rounds/min
Muzzle velocity 780 m/s (2,600 ft/s)
Effective firing range 25 km (16 mi)
Maximum firing range 42 km (26 mi) at 45° elevation

The Japanese "40 cm/45 Type 94 naval gun" (四五口径九四式四〇糎砲?, Yonjūgo-kōkei kyūyon-shiki yonjussenchi-hō) was the biggest naval gun used by battleships in World War II. They were actually 46 cm (18.1 in) guns, but were designated 40 cm (15.7 in) in an effort to hide their true size.


The built-up guns were mounted as the main armament of the Yamato-class battleships that were in service with the Imperial Japanese Navy during World War II. When the turrets and the guns were mounted, each weighed 2,510 tons, which is about the same tonnage as an average sized destroyer of the era.

The Japanese guns were of a slightly larger bore than the three British 18 inch naval guns built during World War I, although the shells were not as heavy. Britain had later designed the N3-class battleship with 18-inch guns but none were built, leaving no Allied naval guns to compare with the Type 94. Unlike the very large guns of other navies they could fire special anti-aircraft shells (Sanshiki) referred to as "beehive".


Some 27 guns were built for the three ships of the Yamato-class battleship. Two thirds of the guns were lost with the sinking of IJN Yamato and IJN Musashi. As built, the design of the barrels was complex. A tube was built then auto-frettaged in three stages. A half length tube was fitted over the first tube and shrunk onto it. The assembly was then wire wound and two additional tubes shrunk over the entire length of the gun tubes. A final inner tube was then inserted down the gun and expanded into place. This inner tube was then rifled to finish the gun. As designed this gun could not cost effectively be relined but instead had to have the entire gun tube replaced due to wear.[1]

Unlike previous designs the turrets, when examined by a US Naval technical team, were found to have nothing in common with previous British Vickers designs used in other Japanese battleships. The shell hoists and powder rams were found to be ingenious though overly heavy designs that allowed a relatively rapid rate of reload. Each gun was independently sleeved allowing for separate elevation.[2]

Range and Flight Time[edit]

With Type 91 AP Shell

Elevation[3] Range Time Of Flight
10° 18,410 yards (16,830 m) 26.05 sec
20° 30,530 yards (27,920 m) 49.21 sec
30° 39,180 yards (35,830 m) 70.27 sec
40° 44,510 yards (40,700 m) 89.42 sec
45° 45,960 yards (42,030 m) 98.6 sec

Impact Angle and Velocity[edit]

With Type 91 AP Shell

Elevation[4] Range Impact Angle Velocity
2.4° 5,470 yards (5,000 m) 3.3° 2,264 feet (690 m)
5.4° 10,940 yards (10,000 m) 7.2° 2,034 feet (620 m)
8.6° 16,400 yards (15,000 m) 11.5° 1,844 feet (562 m)
12.6° 21,870 yards (20,000 m) 16.5° 1,709 feet (521 m)
17.2° 27,340 yards (25,000 m) 23° 1,608 feet (490 m)
23.2° 32,810 yards (30,000 m) 31.4° 1,558 feet (475 m)

See also[edit]


  1. ^ http://www.navweaps.com/weapons/WNJAP_18-45.t94.php
  2. ^ http://www.navweaps.com/weapons/WNJAP_18-45.t94.php
  3. ^ Campbell, Naval Weapons of WWII, p.180.
  4. ^ Campbell, Naval Weapons of WWII, p.180.

External links[edit]