12.7 cm/50 Type 3 naval gun

12.7 cm/50 Type 3 naval gun
12.7 cm/50 Type 3 guns seen in a twin gun Model B turret on Sagiri, 1941
Type	Naval gun
Place of origin	Japan
Service history
In service	1928—1966
Used by	Imperial Japanese Navy Soviet Navy Republic of China Navy
Wars	World War II
Production history
Designed	1926—1927
No. built	approximately 700
Specifications
Mass	4,205 kilograms (9,270 lb)
Length	6.483 metres (21.27 ft)
Barrel length	6.265 metres (20.55 ft) (length of bore)
Shell	separate-loading, bagged charge
Shell weight	23 kilograms (51 lb)
Caliber	127 millimetres (5.0 in)
Breech	Welin interrupted screw
Elevation	depended on mount
Rate of fire	5–10 rpm
Muzzle velocity	910–915 m/s (2,986–3,002 ft/s)
Maximum firing range	18,400 metres (20,100 yd)

The 12.7 cm/50 Type 3 naval gun was a medium-caliber naval gun of the Imperial Japanese Navy used during World War II. It was the standard weapon for Japanese destroyers between 1928 and 1944 (except the Akizuki and Matsu classes). It has been credited as a true dual-purpose gun, but this was more a nominal capability than real, as its bag propellant and need for hand ramming required the gun to be loaded at elevation angles of 5–10°. This dropped its rate of fire to a relatively slow 5–10 rounds per minute, and its training speed of only 6° per second meant that it had a great deal of difficulty engaging enemy aircraft with any chance of success.^[1] After the end of World War II, the gun was exported via the two Japanese destroyers ceded as war reparations to the Soviet Union^[2] and the Republic of China.^[3]