4. Naval Weapons | Section III: Artillery | Chapter IX: Weapons | TM-E 30-480: Handbook on Japanese Military Forces, Technical Manual, U.S. War Department, October 1, 1944 (Lone Sentry)

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4. NAVAL WEAPONS. a. General. In all areas captured from the Japanese, naval guns have been found installed for coastal and antiaircraft defense. These weapons have been of standard naval design, and in many cases appear to have been removed complete (including turret, mounting, etc.) from the decks of ships. It is known that the Japanese have recovered the armament from beached ships and transferred them to land positions. Since they are on pedestal mounts with wide traverse, they not only are used for coastal defense but also may be brought to bear against inland targets. On the following pages are found examples of the naval guns which are most likely to be encountered. Of these weapons the model 10 (1921) 3-inch gun has been most frequently installed. In addition to those weapons described, guns of 127-mm (5 inch) and 8 inch calibers have been captured. The 127-mm guns have been found mounted in pairs in turrets which permit antiaircraft fire.

b. Model 10 (1921) 3-inch gun. (1) General description. The Japanese refer to this weapon (fig. 236) as the "8-cm, 40 caliber, high angle gun." Actual measurement shows it to be 76.2-mm (3 inch). A dual purpose piece on a pedestal mount, it is used for antiaircraft as well as coastal defense. To compensate for muzzle preponderance, an equiliberator is mounted in the pedestal. The recoil system is hydropneumatic, and the breechblock is the sliding wedge type. A noticeable feature is the unusually long recoil cylinder on the top of the tube.

Caliber		76.2-mm (3 inches).
Maximum vertical range		26,000 feet.
Maximum elevation		+75°.
Maximum depression		-5°.
Maximum traverse		360°.
Muzzle velocity		2,240 feet per second.
Sight		Computing type.
Tube length		10 feet 8 1/2 inches.
Rate of fire		10 to 12 rounds per minute.
Weight of HE projectile		12.7 pounds.

c. Model 3 (1914) 12-cm naval gun. (1) General description. Guns of this type (fig. 237) have been encountered on a number of islands in the Pacific Area. No provision has been made on the gun illustrated in figure 237 to provide for use as an antiaircraft weapon, but other weapons of this caliber allegedly are mounted for such purposes. It has a hydropneumatic recoil system and an interrupted thread breechblock.

Caliber		120-mm (4.72 inch).
Length of tube		17 feet 8 inches.
Muzzle velocity		2,700 feet per second.
Maximum elevation		+55°.
Maximum depression		-5°.
Maximum traverse		360°.
Maximum range		16,000 meters (17,500 yards).

(3) Ammunition. Separate loading high explosive with a cartridge case used for obturation.

d. Model 3 (1914) 14-cm naval gun. (1) General description. An orthodox type of naval gun and pedestal mount (fig. 238) which has been used as a coastal defense weapon. It has been found both with a shield and mounted in a hand operated turret (casemate). It has a hydropneumatic recoil system and a truncated cone, interrupted thread breechblock.

Caliber		14-cm (5.5 inch).
Length (tube and breech)		23 feet 8 inches.
Muzzle velocity		2,780 feet per second.
Maximum elevation		+30°.
Maximum depression		-7°.
Maximum traverse		360°.
Maximum range		17,000 meters (18,700 yards).

(3) Ammunition. Separate loading ammunition is used. The projectiles recovered were high explosive, with fuzes designed for use against vessels.