Categories
Japanese

7.7 mm Paratrooper Rifles

Japanese 7.7 mm Paratrooper Rifles

Both of the weapons shown above are basically the same as the Japanese 7.7 mm standard infantry rifle, Model 99. They have been designed, however, to incorporate a takedown feature which enables them to be used by paratroop units. Manufactured at Nagoya Arsenal, they are manually-operated, bolt-action, magazine-fed, clip-loaded rifles.

The modified Model 99 differs from the basic weapon in the following respects: the barrel locking adaptor is secured to the receiver; the barrel is secured into the adaptor by interrupted screw threads; the bolt handle is detachable; and the stock is in two parts.

The Model 2, called “Teraju” by the Japanese, is of much better workmanship than the Modified Model 99. The barrel and front end are detached from the stock at the receiver ring. When taken down, the barrel section is 25 1/2 inches long; the stock 20 1/4inches. Total weight of the loaded weapon is 8.9 pounds. The takedown system is simple and sturdy. The barrel has a straight, unthreaded shank with a lug on the bottom. The shank fits into a socket in front of the receiver. A tapered locking key passes through the receiver (from right to left) and engages in front of the barrel lug. The key cannot be taken out completely, but may be withdrawn far enough to allow removal of the barrel. It is locked in place by screwing a nut on the right side into the receiver wall.

A spring actuated plunger located in the front end of the buttstock locks the barrel and forestock in position. This plunger must be retracted before the barrel can be rotated for takedown.

SPECIFICATIONS

Weight        8.9 lbs.
Length 44″
Principle of operation Manual, bolt-operated
Feeding device Clip
Capacity of feeding device 5 rounds
Ammunition types Model 99 rimless
Type of sight Front: inverted “V” blade on “T” base; Rear: leaf graduated from 328 to 1,640 yds. with aperature sight and aperture battle sight side arms for A.A. fire.
Weight of barrel
Length of barrel 25 7/8″
Length of rifling
Rifling:
   Twist Uniform, right hand; one turn in approx. 10 ins.
   Form Metford segmental
   No. of grooves 4
   Depth of grooves
   Width of grooves
Chamber pressure
Muzzle velocity 2,360 f/s
Maximum range 3,000 yds.
Effective range 600 yds.

Japanese: p. 212.1 (May 1, 1945)

Categories
Japanese

Rifle Grenade Launchers

There are three distinct types of grenade launchers in use by the Japanese. They are known as the Type 2 or cup type, the Type 100 or Kiska type, and the spigot type.

Type 2 Cup Type LauncherThe Type 2, which is patterned after the German grenade launcher of the same type, fits over the front sight of the rifle and has a short rifled barrel. It fires both the 30 mm and 40 mm hollow charge rifle grenades. This grenade weighs 12 1/2 ounces, is 8 inches long, has a maximum external diameter of 1 1/2 inches, and contains 3.8 ounces of TNT. The grenade, which is armed during flight by a base detonating, set-back actuated fuze, detonates upon impact with the target. It will penetrate 3 7/8 inches of mild steel plate.

Type 100 Grenade LauncherThe Type 100 may be used with either the 6.5 mm Type 38 or the 7.7 mm Type 99 rifle. Ordinary ball ammunition is used to launch the grenade from the rifle (the expanding gas from the fired cartridge is utilized to expel the grenade from the launcher), a feature which enables the rifle to be carried with the launcher attached and ready for use as either a rifle or as a grenade launcher. The Type 99 smooth bodied grenade known as the Kiska grenade is the only type used with the launcher. Ranges up to 100 yards may be obtained.

Overall length         8 3/4 ins.
Length of grenade tube 4 1/2 ins.
Diameter of grenade tube (interior) 1 3/4 ins.
Total weight 1 lb., 9 ozs.

Spigot Type Grenade LauncherThe spigot type launcher, which may be used with either the Type 38 or Type 99 rifle, fires the Type 91, Type 3 H.E., and several types of smoke and incendiary grenades. It consists of a rifled barrel threaded to an adapter. The launcher is attached to the rifle at the rear of the front sight mount by two locking arms on the adapter. When a bayonet is fixed to the rifle, additional stability is obtained by the use of a two-pronged lug on the adapter which fits on the bayonet guard.

Length of barrel         150 mm—5.9″
Outside diameter of barrel 27 mm—1″
Inside diameter of barrel 21 mm—.82″
Overall length 107 mm—4.2″
Weight (complete) 15.5 ozs.

Japanese: p. 208.2 (August 1, 1945)

Categories
Japanese

Stereoscopic 2 Meter Base Range Finder Model 97 Type 2

Stereoscopic 2 Meter Base Range Finder Model 97 Type 2

This range finder is believed to be designed for use with seacoast defenses. It is provided with an elbow telescope for tracking purposes and a graphical computer for converting slant range to altitude.

A number of its design features are quite similar to those in the Japanese 2 meter base Height Finder. Similarities are noted in the penta prism mounting, central prism assembly, reticle and eyepiece assemblies, night lighting of scales, and the filter assembly. The instrument is constructed with an outer tube, optical tube, and two tubular diaphragms, all of steel. The outer tube is covered with asbestos treated canvas. The tracking telescope provided with this instrument has a power of 10 diameters and a 5 degree field of view. The body is made of cast aluminum. The tracking telescope is attached to the main instrument by means of a dovetail bracket and is locked in place by a spring latch.

Another accessory, the graphical altitude computor, consists of a pendulum arm inclosed in a circular holder. The pendulum is graduated with a vertical scale in increments of 50 meters from 100 to 1,000 meters, which represents slant range. Angle of site is indicated by a graduated scale on the face of the holder. The cradle has the trunnion bearing arms cast as an integral part of the body. The eyeguard assembly is a copy of the Carl Zeiss design.

SPECIFICATIONS

Power        24
Field of view Undetermined
Diameter of entrance pupil 1.9 ins.
Diameter of exit pupil .08 ins.
Base length 2 meters
Diopter movement +2 to -4 diopters
Measuring limits 500 to 20,000 meters
Inter-trunnion distance 35 1/2 ins.
Overall length 86 ins.
Weight 148 lbs.

Japanese: p. 182 (March 1, 1945)