300 mm Short Howitzer, Type 7

Japanese 300 mm Short Howitzer, Type 7

This howitzer was captured on Luzon. The emplacement, circular in shape and measuring 33 feet in diameter and 8 feet in depth, was camouflaged by a house on rails which was rolled back when the guns were to be fired. A small garden of banana trees was planted around the emplacement to add to the effect.

The howitzer tube is believed to be a built-up type. The liner is rifled with a uniform right hand twist, calculated to be one turn in 9.4 calibers. Two air flasks are mounted on the carriage for blowing out the tube after firing. Two equilibrators are mounted below the tube. The breech mechanism is an interrupted screw type having 8 segments of 20 threads. A percussion hammer firing mechanism is operated by a lanyard. A short cartridge case is used for obturation.

The upper carriage is a rectangular steel frame approximately 18 feet, 9 inches long, and 4 feet, 8 inches wide, fixed to a baseplate. The lower carriage is a truncated steel cone embedded in concrete approximately 6 to 8 feet under the ground. The upper carriage baseplate rests on a rail above a worm wheel, fixed to the lower carriage which engages a spur rack fitted to the base of the upper carriage.

The traversing handwheel is mounted in a horizontal position engaging a vertical shaft which terminates in the worm gear. The elevating handwheels, one on either side of the tube, are mounted on the carriage in a vertical position. A direct shaft from the elevating handwheel terminates in a spur gear which engages the elevating arc.

A panoramic sight is mounted on the right side of the gun.

SPECIFICATIONS

Caliber     305 mm (12 ins. approx.)
Weight (firing position)
Length of tube and breech16 ft., 6 ins.
Length of carriage base18 ft., 9 ins.
Width of carriage base4 ft., 8 ins.
Length (firing position)
Height (firing position)
Width (overall)
Length of bore
No. of lands72
Width of grooves
Depth of grooves
Width of lands
Muzzle velocity (shell)
Max. range (horizontal)—Trans. document13,000 yds.
Max. range (vertical)
Rate of fire
Traverse360°
Elevation, scale reading70°
Depression, scale reading
Length of recoil, scale reading420 mm
Ammunition
Wt. of projectile—Trans. document970 lbs.

Japanese: p. 116.3 (August 1, 1945)

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