Tag Archive for 'type 100'

Double Barrel Flexible Aircraft Machine Guns Model 100 and Model 1

Double Barrel Flexible Aircraft Machine Guns Model 100 and Model 1

These two weapons which are very similar offer the advantage of two guns being mounted in the space occupied by one gun of normal size, thus saving weight in the gun and mount, and space in the plane. A small ammunition supply making frequent magazine changes necessary is a disadvantage partially for the advantages of the double barrel principle.

The operating mechanism for both barrels is housed in a single receiver. This is a single forging, milled to house the two separate actions. The magazine opening is cut out of the top of the receiver, the ejection slot out of the bottom. Each action has its own back plate. The gas piston group resembles the Bren light machine gun in design. The bolt is a steel forging well machined. The gas cylinder tube is constructed of seamless steel tubing and is threaded to the receiver at the rear. The trigger assembly is made up of two separate sear assemblies riveted to the pistol grip framework. Two pistol grips are located about 6 inches apart; the sears are connected to a horizontal trigger bar mounting a trigger on either end. Both guns may be fired by depressing either trigger. The magazine is the saddle-drum type. Each side holds 50 rounds and feeds one gun. Each side has its own spring so that, in the event of a jam affecting one barrel, the other gun may continue to fire.

The Model 1 (1941) gun appears to be basically the same weapon as the earlier model, Model 100 (1940) which is shown at the bottom of the illustration. The Type 1 gun shown at the top of the picture has a head or shoulder rest attached to the gun. This rest is made of wood and canvas and is attached to the gun with steel frames. The specifications were secured from the earlier weapon.


Caliber         7.92 mm
Weight of gun 36 lbs.
Length (overall) 37.5 ins.
Length of receiver 16.25 ins.
Length of barrel 24.5 ins.
Length of rifling 22.37 ins.
Diameter of bore—
   across lands 0.310 in.
   across grooves 0.313 in.
Number of lands 4
Width of lands 0.0781 in.
Width of grooves 0.1718 in.
Depth of grooves 0.003 in.
Twist of rifling Uniform R.H.
Pitch of rifling 7° (approx.)
Type of operation Gas
Type of fire Automatic only
Type of feed Magazine, saddle-drum type
Capacity of magazine 100 rounds
Weight of magazine empty 7 3/4 lbs.
Weight of magazine filled 13 3/4 lbs.
Ammunition A.P.—Incendiary
Rate of fire (estimated) 400-600 r.p.m.
Range 250 to 350 meters

Japanese: p. 216.1 (March 1, 1945)

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)

8 mm Submachine Gun, Type 100 (1940)

8 mm Submachine Gun, Type 100 (1940)

The Japanese 8 mm submachine Gun, Type 100, is an automatic, air-cooled, magazine-fed, straight blowback-operated type, firing from an open bolt. Its basic design strongly resembles that of the German submachine guns. The weapon may be broken down into three main groups: a receiver which contains the bolt and driving spring, a barrel assembly, and a wooden stock assembly containing the trigger and trigger guard. A considerable amount of rough welding is used on the weapon; the front sight, bayonet lug, barrel lock, magazine well, driving spring guide, and trigger guard have all been attached to the rifle by this method. An unusual feature of the gun is a replaceable firing pin which screws into the face of the bolt.

The weapon has a high cyclic rate of fire, estimated between 800 and 1,000 rounds per minute.

It differs from the Type 100 (1940) Paratrooper’s rifle, described on page 204.1, in the following respects: it does not have a folding stock; a standard bayonet can be mounted directly on barrel and barrel jacket; and the rear sight is fixed rather than of the sliding ramp type.


Caliber      8 mm (.315 in.)
Weight with sling and magazine9 lbs., 2 oz.
Weight of magazine9 oz.
Length (overall)36 ins.
Sight radius
Principle of operationStraight blowback
Feeding deviceCurved box magazine
Capacity of feeding device30 rounds
Cooling systemAir
Ammunition types8 mm pistol
Rate of fire (cyclic)800-1,000 rds. per min. (est.)
Type of sight—Front:Inverted “V”
                      Rear:“V” with small peep additional.
Weight of barrel
Length of barrel9 3/16 ins.
Length of rifling8.3 ins.
   TwistR.H .
   No. of grooves6
Muzzle velocity1,050 f/s
Maximum range
Effective range

Japanese: p. 204.2 (August 1, 1945)