Japanese Type 92 (M1932) 7.7mm Heavy Machine Gun
By Robert G. Segel
For military weapons adopted officially before 1940 the Japanese had a distinct system of identifying these weapons using two basic methods. One method referred to the Type number, which represented the last two digits of the Japanese Jimmu Year. For the Type 92 heavy machine gun, this represented the year 2592, or 1932 on the Gregorian calendar. This designation is noted in three Japanese kanji characters arranged in a vertical column on top of the gun’s receiver. Another method is shown in markings on the left side of the Type 92 receiver: the symbol of the manufacturer; the gun’s serial number; the Showa Era date of manufacture (the Showa Era was the period of Emperor Hirohito’s reign beginning in 1926 and ending upon his death in 1989); and the symbol of the supervising arsenal. The manufacturer of the Type 92 example featured in this article is Tokyo Gas and Electric Company, the Showa Year 14.5 represents May, 1939 and the tri-petal symbol represents the supervising Kokura Army Arsenal.
Long secluded as a feudalistic empire, Japan began her industrialization at the end of the 19th century. With a great deal of European advice, assistance, and influence, Japan began properly to organize and equip its military. By the beginning of the 20th century, machine guns, however, were still new and novel. Even European advisors were unclear as to their tactical importance, thinking that machine guns were fundamentally a defensive weapon designed to counter mass frontal attacks. But the Japanese quickly realized the potential of the machine gun’s offensive support capabilities, and they purchased a version of the French Hotchkiss Model 1897; preparations for the manufacture of the Hotchkiss gun in Japan were begun in 1898. This gun was chambered for the 6.5x50mm semi-rimmed Arisaka rifle cartridge and can be identified in photographs by the seven doughnut cooling rings rather than the normal French manufactured five rings. It is interesting to note that most of Japan’s European military advisors were German, and one can question why they chose the French Hotchkiss. The records are not clear, but one can assume that the Japanese wanted an air-cooled machine gun and believed the Hotchkiss design to be the best, most robust and dependable that was available at that time.
Japan soon recognized the battlefield advantages of their new heavy machine gun in the Russo-Japanese War of 1904-1905. Machine guns were used extensively for the first time and the Japanese were the first to use them in a modern war, as opposed to a colonial war. The Russian Far Eastern Fleet was blockaded at Port Arthur in Manchuria and the land side was heavily fortified by Russian forces. The Japanese used three divisions in the attack on Port Arthur and each division had twenty-five Hotchkiss guns. The Japanese amassed their machine guns for direct overhead fire into the strong, yet clearly visible, Russian defenses. The resulting victory established the role of the heavy machine gun in offensive operations.
Taisho 3 (1914) Nen Shiki Kikanju
Taisho 3 refers to the year of production of a heavy machine gun that preceded the Type 92, in this case, in the third year of the then reigning Emperor of the Taisho Era or, in the western calendar, 1914.
In 1914, Colonel Kirijo Nambu set about to upgrade the older Model 1897 Hotchkiss and again it was chambered for the 6.5x50mm semi-rimmed (Model 30) Arisaka rifle cartridge. Though the gun was basically the French Hotchkiss Model 1914, Colonel Nambu made some changes in the bolt locking mechanism and backplate group. He also redesigned the ejection system and, because of the abrupt ejection the Taisho 3, he employed an oil reservoir and brush application system in the feed block to assure a smooth extraction of the cartridges after firing. The Taisho 3 is easily recognized by spade grips on the rear rather than the folding hand grips used on the later Type 92.
Type 92 (M1932) Kyuni Shiki Jukikanju
The moderately powered 6.5mm rifle cartridge was not well suited for machine guns due to the relative lack of taper which caused ejection problems and because of its comparative lack of power. This became evident in Japan’s conflict with China. In 1932 General Nambu began to make changes in the Taisho 3 to enhance its performance. This upgraded version was known as the Type 92. The Type 92 was chambered for the 7.7x58mm semi-rimmed cartridge that was based upon the British .303 cartridge. The 7.7mm cartridge had much greater range, penetration and general destructive power over the 6.5mm and it brought the gun up to its true potential. Other improvements were made to the trigger assembly and the spade grips were replaced with a pair of folding pistol grips. Importantly, the sights were changed. The Type 92 had a mechanical peep sight fully adjustable for windage and elevation, whereas the Taisho 3 merely had a tangent sight with no provision for windage adjustment. The Type 92 also had provision for the use of a variety of telescopic sights in various powers and configurations. Other than these refinements, the Type 92 was mechanically the same gun as the Taisho 3. Many of the Taisho 3s were arsenal rebuilt to the Type 92 configuration.
Tokyo Gasu Denki
The Type 92 featured in this article was one of the last to be manufactured by the Tokyo Gas and Electric Company, also known as Tokyo Gasu Denki, or as TGE. TGE was a private arms manufacturing company in Tokyo and operated under the supervision of various arsenals during its production history. These included the Koishikawa Arsenal prior to 1935, the Tokyo Army Arsenal Number One from 1935-1936, and the Kokura Army Arsenal after 1936 until at least August of 1939 when Tokyo Gas and Electric was merged with Hitachi Seisakusho and ceased to exist as a separate entity. Later that same year, the Type 92 was being produced by Hitachi Heiki (Hitachi Weapons Company), descendent of the parent Hitachi Seisakusho.
It is not known at this time exactly when Tokyo Gas and Electric began producing the Type 92 heavy machine gun. Complete guns were being made in early 1935 and it is likely the first guns appeared in late 1934, with tripods and other parts being made earlier, perhaps very soon after the gun’s official adoption in 1932. Taisho 3 heavy machine guns were already being made at TGE in 1932 and the manufacture of the Type 92 there required only a minimum of retooling and the addition of some new machinery to make the redesigned parts of the Type 92.
Serial numbers of Type 92s manufactured at TGE appear to begin at 10,000 and ended at the mid-16,000s when TGE merged with Hitachi in August of 1939. Thus, over a seven-year period, TGE produced about 6,500 Type 92s. TGE continued production uninterrupted throughout the management transition from TGE to Hitachi and Type 92 serial numbers made by Hitachi begin where TGE serial numbers leave off.
All Tokyo Gas and Electric Type 92 heavy machine guns show high quality workmanship and careful fitting of parts. However, the steel used in their construction tended to be soft, showing little evidence of heat treatment other than topical flame hardening of moving parts to reduce wear. The finish of the Type 92 is a uniformly high quality rust blue. No production shortcuts were used at any time during its manufacture by TGE. The design of this weapon remained virtually unchanged from the beginning of its production until production ceased at the end of World War II. The Type 92 was a durable and reliable weapon used with great effectiveness by the Imperial Japanese military forces.
The Type 92 was equipped with a small number of accessories. These included:
- An anti-aircraft (AA) extension adaptor to be mounted on the tripod for anti-aircraft operations.
- A front anti-aircraft ring and rear blade sight. The AA ring sight is placed in the ring sight base located in front of the receiver and the rear AA post sight is slipped into the channel on the rear sight mechanism. The front and rear AA sights were kept in a fitted metal case when not in use.
- Three different telescopic sights were used, each with a fitted case.
- Tool and spare parts box. The takedown tools are particularly important and necessary for removal of the gas-jet plug and barrel.
- Handles for carrying the gun and tripod.
- A gun cover was also issued.
Three types of optical sights were used with the Type 92 heavy machine gun. The first was the Model 93 (1933). The 6-power Model 93 is a periscopic sight measuring 8.4 inches from top to bottom. The eyepiece is located well above the top of the receiver and it was used for laying the gun. It was removed before firing. The Model 93 optical sight was affixed to a large base unit that attached to the top of the receiver. This base unit was separate from the telescopic sight and contained the various adjusting wheels.
The second type of optical sight was the Model 94 (1934). This 5-power sight was also a periscopic type measuring 12.8 inches from top to bottom. The eyepiece is level with the top of the receiver and was better supported on the sight base unit. This sight was affixed to the same large sight base unit with the adjusting wheels that was used with the Model 93 and was attached to the top of the receiver.
The third, and final, type of optical sight was the Model 96 (1936). This sight is a 4-power telescopic sight which mounts directly on top of the receiver and it may be used while firing. The elevation wheel is located above and to the right of the eyepiece and is marked from 1 to 50 mils plus and minus. The deflection knob and scale are located on the left side of the sight. The single complete unit attaches directly to the top of the receiver.
The Type 92 tripod weighs 61 pounds. An elevating wheel is located to the front that raises and lowers the tripod head to the desired height. As the tripod head is lowered, the bottom of the vertical support column protrudes out the bottom of the tripod. A leather boot is attached to the bottom of the tripod to encompass and protect this vulnerable opening from dirt, mud and sand. The gun has two (left and right) trunion studs located just forward of the receiver that lock into receptacles located on top of the tripod head. Fine adjustment controls for traverse and elevation are located on the tripod head beneath the weapon.
A unique feature of the Type 92 tripod is the means by which to easily carry the assembled gun and tripod (totaling 122 pounds) by three or four men in the manner of carrying a litter. The two front legs of the tripod each have a socket welded in place near the foot and are keyed to accept the carrying handles. The rear leg also had a keyed receptacle to accept a “U” shaped carrying handle. Wood or bamboo could also be used in field expedient situations.
The Type 92 (1932) heavy machine gun is a modified Hotchkiss-type weapon. Barrel life is unusually long as the gun rarely overheated due to the slow cyclic rate of fire and feed strips containing only 30 rounds and with its great number of cooling rings (25). The gun uses Model 92 (1932) 7.7mm semi-rimmed ammunition in ball, tracer and armor-piercing. An incendiary round can also be used. Another unique feature of the Type 92 is that besides having an ejection port cover that locks closed and is opened by retracting the cocking handle; it also has a feed strip entrance port cover that incorporates a feed strip roller bar that also opens when the cocking handle is retracted. The Earlier Taisho 3 version proved itself during the long wars against China in the 1930s and the later modified Type 92 was the standard machine gun during World War II. The Type 92 was nicknamed the “Woodpecker” by Allied soldiers during World War II due to its distinctive, slightly hesitant sound when firing. Since the weapon used a 30-round feed strip that hung somewhat heavily if not supported by the hand of the assistant gunner on the left side of the gun when first inserted into the feedblock, the first few rounds fired were relatively hesitant before picking up speed. This caused a sound uniquely characteristic to this weapon and the gun easily was identified in action.
- Safety. Turn the trigger thumbpiece clockwise for “safe.” When the feedstrip is removed, the bolt is locked in the rear position. When a strip is inserted and the bolt is unlocked, the gun can be fired by pressing on the trigger thumbpiece.
- To load and fire. Put the traversing handles into the lower, or firing position. Pull back the cocking handle and push it forward. The feed and ejection opening ports will automatically open when the cocking handle is moved. Insert a strip of ammunition from the left side of the feed mechanism with the rounds uppermost. The gun is now ready to be fired. The gun will continue to fire as long as the trigger thumbpiece is pressed forward or until the ammunition is expended, at which time the now empty feed strip is ejected from the right side of the weapon and the holding pawl rises up and holds the bolt open until the weapon is reloaded with a fresh ammunition strip. To adjust the gas cylinder, screw the gas cylinder plug in or out, enlarging or decreasing the length of the gas cylinder until the gun functions properly.
- To unload. Pull out the feed holding-pawl arm hook underneath the feedway on the left side of the receiver. Remove the feed strip. Check the chamber to be sure it is empty.
- Always be sure weapon is unloaded and safe before disassembly.
- Backplate. Remove the backplate pin by turning it down to a vertical position and then pulling it out to the left. Hold the backplate in place against the pressure of the operating spring and then carefully remove the backplate group, buffer assembly and operating spring.
- Bolt. Pull the cocking handle to the rear, and remove the gas piston, bolt lock and bolt. Align the lugs on the cocking handle with the openings on the side of the receiver and remove the cocking handle.
- Oiler. Push forward on the oil reservoir lock and raise up on the rear of the oil reservoir. Remove the oil reservoir retaining screw and lift the oil reservoir up and off of the feedblock.
- Barrel. Remove the gas jet cover from the bottom of the gas cylinder. Unscrew the gas jet from the barrel using the specialized gas jet removal tool found in the tool and spare parts box. Remove the barrel nut by unscrewing. Using the special barrel removal tool found in the tool and spare parts box, unscrew the barrel sleeve. Then turn the barrel one-half turn to the right and pull it out.
- Feed mechanism. Locate the holding pin located at the front and bottom of the feed box. Rotate this pin one-half turn in a downward direction and then pull it out. Remove the holding pawl and holding-pawl spring. Align the marks on the feed slide with the marks on the feed box, and drift the feed-slide pin out to the front of the feed box. Slide the feed slide to the left, removing the feed pawl and feed-pawl spring at the same time.
- Assembly. To assemble the weapon, proceed in the reverse order to that followed in stripping.
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