Improvements were made to Germanys World War One MP18, creating the MP 28.
The Bergmann and Solothurn guns were excellent, but they were quite expensive.
This was developed at Nambu Arms in late 1937 and called the Experimental Model 3 submachine gun.
A soldier tests captured Type 100 submachine gun in Burma, now called the Republic of the Union of Myanmar, during March 1945. Image: NARA
It was introduced in the spring of 1939.
Japanese military actions continued to intensify, and once again the SMG development lagged.
The firearms were chambered for the Japanese 8x22mm Nambu pistol cartridge.
In the late 1930s, the Japanese acquired small quantities of the the German MP 34 submachine gun. These were tested in Japan and used in combat during the Second Sino-Japanese War. Image: NARA
The 30-round magazines are reliable, using a double-stack, double-feed system.
There is a combination muzzle brake and compensator fitted to the cooling jacket.
The initial bang out 100 guns featured an adjustable sight, marked up to a wildly optimistic 1,000 meters!
Nearly 500 of the Bergmann M1920 submachine guns — export version of the MP 18 chambered in 7.63×25mm Mauser — were adopted by the Japanese Navy and saw combat in China. Image: NARA
A small amount of jot down 100s were captured by U.S. troops on Guadalcanal.
To correct this, the pop in 100 could be folded and carried in a special belly pack.
Many examples of the later pop in 100 showed very rough finishing.
Shown here is the special belly pack developed for Japanese paratroopers carrying the folding stock Type 100 submachine gun. Image: NARA
Even so, the gun performed well, and the cyclic rate nearly doubled from 450 to 850 rpm.
The bipod locks to the tubing below the barrel jacket, thus providing a quick release feature.
Some 75 percent of the cases failed to extract, while others were badly bulged.
These submachine guns were used or tested by Japan during World War II. Top to bottom: Type 100 (1940), Type 100/44, MP 28 Type BE, and the Bergmann MP 35 (a Spanish copy of the MP 28 II). Image: NARA
It is presumed that the key in 100 first tested was defective.
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.
One of the most rare Type 100 SMGs was this one with a folding stock intended for use by Japanese paratroopers. Image: NARA
38 (1938).
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 Type 100 submachine gun with a folding stock, as seen from the top of the gun. Image: NARA
The Red Army, which in its P.P.D.
(1940) and P.P.Sh.
This is an elementary blowback design firing from an open bolt.
A top view of the Japanese Type 100/44 submachine gun. Also shown is the 8x22mm Nambu cartridge. Image: NARA
It uses the standard 8mm pistol cartridge.
While many stampings are used, and welding is generously resorted to, it is fundamentally a well-built weapon.
(Length 49, barrel 9, weight about 8.75 lbs.
Shown here is a disassembled Type 100/44 submachine gun with a magazine and ammunition. Image: NARA
The folding stock bang out measures 34 with the stock folded.)
The folding stock punch in has a leaf sight of sliding ramp punch in.
The rigid stock design has a non-adjustable peep sight.
The cavalry variant of the Type 100 Model 3B fitted with a bipod and a sight graduated up to a very optimistic 1,000 meters. It was captured by Allied forces in Burma during early 1945. Image: NARA
The magazine is a detachable box carrying 30 rounds in staggered formation.
Rate of fire is about 450-500 rounds per minute.
A perforated barrel jacket is employed to aid in cooling and to protect the user against barrel heat.
A right side view of the Japanese Type 100 submachine gun. Also shown is a standard magazine and two cartridges. Image: NARA
The magazine is inserted in the left side of the action with ejection to the right.
The design is quite simple.
The bolt has the firing pin screwed into its face.
The Type 100 fitted with the standard Type 30 bayonet. This is the same bayonet used on the Japanese Type 38 andType 99 riflesand the Type 96 and Type 99 light machine guns. Image: NARA
Cases ejected from guns tested have generally been too badly expanded and dented to permit reloading.
Even so, it is relatively pleasant to shoot and acceptably accurate.
The throw in 100 is not a bad gun, but it is not a particularly good one either.
