Type 3 120 mm 45 caliber naval gun

Type 3 120 mm 45 caliber naval gun
Bow gun on Yunagi, September 1936
Type	Naval gun Coast defense gun
Place of origin	Empire of Japan
Service history
In service	1918-1945
Used by	Imperial Japanese Navy
Wars	World War I World War II
Production history
Designed	1914
Variants	Type 11
Specifications
Weight	3,240 kilograms (7,140 lb)
Barrel length	5.4 metres (18 ft) bore
Caliber	120 millimetres (4.72 in)
Action	manual
Breech	single motion interrupted screw Welin breech block
Elevation	-7° - +33°
Traverse	+120°- 120°
Rate of fire	5-6 rounds per minute
Muzzle velocity	825 m/s (2,710 ft/s)
Effective firing range	16,000 metres (17,000 yd) at 33°

Type 3 120 mm 45 caliber naval gun was a Japanese naval gun and coast defense gun used on destroyers, submarines and torpedo boats of the Imperial Japanese Navy during World War I and World War II. The proper title of the gun under the Japanese naval artillery naming system is 12 cm/45 3rd Year Type naval gun. Other guns using this naming system are the 41 cm/45 3rd Year Type naval gun, 20 cm/50 3rd Year Type naval gun, 15.5 cm/60 3rd Year Type naval gun and the 12.7 cm/50 Type 3 naval gun.

The 12 cm/45 gun designed in 1914 was an indigenous variant of the British QF 4.7 inch Gun Mk I - IV, produced under license from the Elswick Ordnance Company and known as the "Type 41". Later in 1921 the 12 cm/45 gun was used as the basis for a high-angle anti-aircraft gun, designated the 12 cm/45 10th Year Type The "Third Year Type" refers to the Welin breech block used and this should not be confused with the later Type 3 12 cm AA Gun developed by the Imperial Japanese Army in 1943. In the Japanese Army artillery naming system, "Type 3" refers to the year of introduction, rather than the type of breech block used.

A re-design in 1922 called the 12 cm/45 11th Year Type (Model 1922) with a shorter gun barrel and a horizontal sliding breech-block was used on submarines and torpedo boats. The 12 cm/45 was manually loaded and fired a 20.3 kilograms (45 lb) High-explosive, a illumination shell or after 1943 an anti-submarine shell.