10 cm/65 Type 98 naval gun
The 10 cm/65 Type 98 naval gun, also known as the long 10cm high-angle gun, was a light caliber naval gun of the Imperial Japanese Navy used during World War II, employed on the aircraft carrier, the light cruiser, and destroyers.
The gun was considered by the Japanese to be their finest anti-aircraft artillery weapon. It had excellent elevation and reach and could traverse quickly. Its rate of fire was good, though not as good as the U.S. 5”/38 dual-purpose gun. Its directors were also poorer, and the 10 cm/65 lacked the radar proximity fuse developed by the Allies. After the end of World War II, the gun remained in service on the two Japanese destroyers ceded to the Soviet Union and the Republic of China as war reparations. When used as a land-based weapon it suffered from needing considerable construction work in preparation for emplacement, which limited its usefulness to static defense. Nevertheless, 32 mounts were deployed for defense of the Japanese homeland, and another three on Iwo Jima, along with two more at Balikpapan. The Allied forces would first captured a shore-based twin-mounting of this weapon at Iwo Jima.
Description
The 100 mm 65 caliber Type 98 gun utilized a horizontal sliding breech, in addition to either monobloc or replaceable liner construction of the barrel. The gun featured a spring-powered rammer that was cocked by means of the recoil of the gun being fired; this allowed the rammer to load the gun at any elevation.116 guns went to ship-based mounts: 12 for Taiho and 8 each on Oyodo and the 12 Akizuki-class destroyers. A shortcoming of the gun was that it had a service life of only 350-400 full charges, due to its high muzzle velocity.