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"New Notes on 8-mm Submachine Guns" from Intelligence Bulletin, July 1945

[Intelligence Bulletin Cover]   Text of a U.S. intelligence report on the Japanese Type 100 submachine gun, from the Intelligence Bulletin, July 1945. Two illustrations in the original have not been included.

[Editor's Note: The following article is wartime information on enemy weapons and tactics published for Allied soldiers. More accurate data on Japanese weapons and tactics is available in postwar publications.]



Complete specimens of all three known versions of the Japanese Type 100 (1940) submachine gun are now in Allied hands. The three versions thus far identified are: (1) the earliest version with removable bipod and bayonet; (2) the paratroop version, with removable bipod, bayonet, and folding stock; and (3) the latest version, with bayonet but no bipod. It was known prior to the capture in Burma of the earliest version that this unusual weapon was fitted with a bipod. Recovery of an actual specimen with bipod reveals that the bipod secures around the barrel jacket by means of a collar. The bipod locks to the tubing below the barrel jacket, thus providing a quick-release feature. Inspection of the various guns shows that the paratroop version of the Type 100 can also take the bipod, and that the paratroop gun is identical to the earliest version except for the folding stock. No bipods have yet been reported as having been found on, or near, captured paratroop Type 100's.

Since the bipod is a most unusual addition, the appearance of the third version of the Type 100 without this feature was not at all surprising. This latest type of Type 100 (briefly described in Tactical and Technical Trends, No. 57) is fitted to take the standard Type 30 (1897) bayonet, in line with the official Japanese doctrine which urges fighting with cold steel.


Although preliminary tests indicated that Japanese 8-mm pistol ammunition would not function in a Japanese 8-mm Type 100 (1940) submachine gun, further tests now show that such use of the ammunition is entirely practical. In the first tests, caliber 8-mm pistol ammunition packaged for the Type 94 (1934) pistol functioned very badly when used in a later-model Type 100. Some 75 percent of the cases failed to extract, while others were badly bulged. However, tests with other Type 100 guns now show that the performance with ordinary Japanese pistol ammunition is entirely satisfactory. It is presumed that the Type 100 first tested was defective.

In spite of modification of the Type 100 series to the latest form, this type of submachine gun leaves much to be desired. For one thing, it represents a manufacturing problem. The Japanese have made no effort to ease production bottlenecks by the extensive use of stampings throughout the weapon. They have manufactured a Bergmann-type gun, instead of one patterned after the mass-production German "burp gun," the Schmeisser M.P. 38 (1938). From the operational point of view, U.S. Army Ordnance tests indicate that its cyclic rate of 800 to 1,000 rounds per minute is too high for maximum effectiveness. U.S. Army findings in this respect are bolstered by the experience of other battle-tested armies. German submachine guns have a rate of fire around 500 rounds per minute. The Red Army, which in its P.P.D. (1940) and P.P.Sh. (1941) tommy guns had weapons with a 1,000-round per minute cyclic rate, later standardized on their M1943 submachine gun with a cyclic rate of 650 rounds per minute. In an effort to correct the drawbacks inherent in a high rate of fire, the Japanese have fitted a type of compensator to the latest version of their Type 100.

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