Intelligence report on the Japanese 10 cm Type 98 (1938) Dual Purpose Gun from Japanese Artillery Weapons, CINCPAC-CINCPOA, Bulletin 152-45, July 1945.
10 CM DUAL PURPOSE GUN TYPE 98 (1938) This twin mount dual purpose gun was encountered for the first time on Iwo Jima. With its high muzzle velocity and long range it is one of the Japs most powerful anti-aircraft and medium caliber coast defense weapons.
Recognition is made easy by the extreme length of the barrels (65 calibers) and the two symmetrical horizontal sliding type breech blocks. Ammunition loading trays are provided on either side of the breech blocks to aid in loading. The Navy type riveted shield revolves around a steel base.
A four meter rangefinder was found with the battery on Iwo, and although no director was recovered, Types 94, 2 and 4 directors may be used with these weapons.
With the electric motor provided to facilitate elevation and traverse, a speed of over 16 feet per second for each is possible. A rate of fire (firing both barrels) of 456 rounds per hour (8 rds per minute) is allegedly possible.
Characteristics
Caliber 100 mm (3.93 in.) Length of bore 65 calibers Muzzle velocity 3,280 ft/sec. Maximum range (horizontal) 20,400 yds. Maximum range (vertical) 44,300 yds. Effective range (vertical) 34,400 ft. Rate of fire 15 rds/min. Elevation 90 degrees Depression 10 degrees Weight of projectile 28.7 pounds
