Type 99 Nambu LMG
By Mark Genovese

I’m sure the many SAR readers understand that the State of Hawaii was a vast staging depot for the US military during the last three wars. Consequently many captured weapons were traded, sold and even lost in local card games. Recently I got a call from a friend in law enforcement asking if I could come to their office and help identify an abandoned rifle. When I arrived I was surprised to find an absolutely beautiful Japanese Type 99 LMG complete except for the flash hider and magazine. The rifling and all internal components were in superb condition, the exterior had a light brown patina and the wood was well worn. I inquired about its local history and was told the story passed down with the weapon. It was supposedly retrieved from a downed Japanese aircraft in the battle of Pearl Harbor and had been wrapped in a towel and stored in an open carport since the end of World War II. I felt at the time, more than likely this was an urban myth because this type of ground gun would never be found in fighter aircraft. I received the correct historical background from Professor Ed Libby of Bowdoin College that put the matter to rest (see sidebar below). The Type 99 is an improved version of the Type 96, itself a copy of the Czechoslovakian VZ26 designed by Zbrojovka Brno arms factory in the early 1920s. The Type 99 fires the 7.7x58mm Arisaka round from an open bolt. It is 46.50 inches in length; weight unloaded is 23 pounds; barrel length is 21.50 inches with four grooves and a right-hand twist. It has a 30-round, staggered-column, detachable, box-type magazine and a cyclic rate of 850 rounds per minute with a muzzle velocity of 2,350 fps. It was in production from 1936 to 1945. When the Japanese Army found it necessary to adopt the 7.7x58mm rimless cartridge, Arisaka improved the Type 96 LMG and introduced the Type 99. The new 7.7x58mm rimless round did not require oiling, as there was slow and adequate primary extraction designed to give an unseating movement before a more rapid extraction. This system reduced the ruptured case stoppages often encountered with the caliber 6.5x51SR Type 96. Machining tolerances were held to very fine limits and a new far better style of quick-change barrel was employed. Other welcomed improvements included provision for the adjustment of the cartridge headspace, a large flash hider, and an unusual monopod found underneath the butt. The receiver is equipped with two dust covers. One manually opens on top of the weapon, protecting the magazine port and internal mechanism. The second is spring loaded at the ejection port and functions like that of the M16, flipping open when the weapon is cocked. The Type 99 can be found fitted with an unusually long bayonet and/or a low power telescopic sight. The front sight is protected by wings and the rear sight an excellent peep.

My friend was under the impression this historical war trophy had to be forfeited to the BATF and destroyed. He was happy to find out there is an option: the Form 10 Application for Registration of Firearms Acquired by Certain Governmental Entities. Form 10’s are an easy way to dispose of unregistered NFA weapons. The department need not disclose where the firearm came from, as it says in section 5. After making some calls they found the War museum on Guam had a Type 99 but it was retrieved from a coral reef and in horrible condition. To make a long story short, we made them an offer they couldn’t refuse. Very soon this historical Japanese Type 99 LMG, found in a carport on the small island of Maui will retire to another island where it very well may have been fired in anger some fifty eight years ago.

Type 99 Nambu LMG, (serial number 6358)
By Ed Libby

This Type 99 Nambu Light Machine Gun was manufactured by the Kokura Army Arsenal in Kokura, Fukuoka Prefecture, Japan. By 1929 this arsenal had begun to take on the production of small arms which long had been the responsibility and function of the expansive Koishikawa Army Arsenal in Tokyo; the Kokura Army Arsenal became one of the largest producers of small arms in mainland Japan, and it had a major authority for the supervision of small arms production within the Japanese arsenal system. The markings on the right front of the receiver identify the origin of this Type 99 LMG. At the left in the top line of receiver markings, preceding the Kanji characters or “99 Type,” is the Kokura Army Arsenal symbol, which represents four stacked cannon balls as viewed from the top. The gun’s serial number is immediately below this marking and it is preceded by the Kana syllable “nu,” or “10,” which is inscribed in a circle. All Type 99 LMGs of Kokura Army Arsenal manufacture identified to date have serial numbers preceded by this Kana syllable marking; presumably this syllable designates the only production run of Type 99 LMGs made by Kokura. Directly below the serial number is the gun’s date of manufacture, in this case “Sho(wa) 18.10,” or October, 1943. The Showa Era was the period of the reign of the Emperor Hirohito, which began in 1926 and ended on January 7, 1989 with the Emperor’s death. The number to the left of the period in the manufacturing date represents the gun’s year of manufacture with respect to the beginning of the Showa Era. The number to the right of the period in this date represents the month of manufacture.

The Type 99 LMG design originated with Lt. General Kijiro Nambu at a private arms manufacturing company in Tokyo, Chuo Kogyo Kabushiki Kaisha, Ltd., where he served as part owner, designer, and adviser until his retirement in 1943. Essentially the Type 99 LMG was a slightly redesigned and strengthened 7.7mm version of the 6.5mm Type 99 LMG then in service, which also was designed by Nambu and which, however unofficially, bore his name. Nambu was Japan’s premier designer of military small arms, and he was well known for his design of his automatic pistols and of the Type 92 heavy machine gun.

The Kokura Army Arsenal took over much of the small arms production from the Koishikawa Army Arsenal in Tokyo after the Great Earthquake Disaster of 1923 devastated Tokyo and parts of this arsenal; the extent of this devastation precipitated the military decision to disperse ordnance production throughout Japan. Constructed as part of this dispersal plan, Kokura was developed sufficiently by 1936 to complete the transfer of the great majority of small arms production from Koishikawa, and the Koishikawa Army Arsenal was reorganized to become Tokyo Army Arsenal Number 1, an arsenal of several factories, which manufactured ordnance, and munitions of all kinds during its period of operation. In 1941, in the early part of the Pacific War, Kokura Army Arsenal consisted of five factories, one research and development laboratory, and one small proving ground located at Koga, Fukuoka Prefecture. Because of heavy bombing raids in 1944, Kokura Army Arsenal factories and the laboratory were moved to Hita City, Oita Prefecture and, although this move was effected in June of 1945, production there was rather limited until the war ended in August of that year. The arsenal mark described above which was used by the Koishikawa Arsenal was continued in use by both the Tokyo Number 1 and Kokura Army Arsenals.

Type 99 LMG production began at Kokura Army Arsenal in 1942 and, as research data collected reveals, was continuing in November of 1943. Possibly Type 99 LMG production by Kokura Army Arsenal continued until war’s end in 1945, but documented information suggests that the production of this weapon ceased sometime in early 1944, perhaps because of U.S. bomb damage to Kokura facilities, because of factory relocation, because of a shift in production priorities, because of materials shortage, or because of combinations of these reasons. Although it is not known at present just how many Type 99 LMGs were produced by Kokura Army Arsenal, a conservative estimate is 7,000 guns. Type 99 LMG serial numbers on Koukura-made guns were consecutive, beginning presumably at “1” and continuing perhaps to approximately 7000.

All Kokura-made Type 99 light machine guns examined by or reported to this author evidence high quality of manufacture of this weapon, with all original design features retained throughout the production period, with no production shortcuts to be noted. Workmanship is very good and parts are fitted carefully, although exterior tool marks are typical. The finish employed is a hot chemical blue black.

The Type 99 Light Machine Gun was made at Kokura and Nagoya Army Arsenals, and at Mukden Army Arsenal in Manchuria; also it was made by two civilian companies in Tokyo - by Hitachi Seisakusho and by Chuo Kogyo Kabushiki Kaisha, Ltd. The standard light machine gun employed by the Japanese military forces, the Type 99 LMG was an accurate, durable, and reliable weapon. US forces encountered the Type 99 LMG in nearly all of their campaigns of the Pacific War and this weapon appeared in increasing numbers in the later battles of that war.

This article first appeared in Small Arms Review V7N1 (October 2003)
and was posted online on October 11, 2013


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