|Length (stock closed/open)||889 mm|
|Barrel length||228 mm|
|Rate of fire||450 rounds per minute (~800 for 1944 model)|
|Magazine capacity||30 rounds|
The Type 100 submachine gun was developed by famous Japanese small arms designer, gen. Kijiro Nambu. First prototypes of this submachine gun were submitted for Japanese Army trials in 1939, and the new weapon was formally adopted in 1940 (2600th year in contemporary Japanese calendar). This submachine gun was initially produced in two forms, as a standard infantry gun with solid stock and as a paratrooper weapon, with side-folding butt. In 1944, following the decline in Japanese industry, the basic Type 100 submachine gun was simplified, and put in production in this form. Overall, several tens of thousands of Type 100 submachine guns were manufactured in Japan by Nambu company and Nagoya and Kakuro arsenals between 1940 and 1945. The gun was of more or less conventional design, but towards the end of the war it was severely plagued by poor quality of materials and workmanship, as well as by marginally powerful ammunition, also of dubious quality (especially during the latter part of the war). After the war it became obsolete in Japan, but some were encountered during latter local conflicts in the SE Asia region.
The Type 100 submachine gun is a simple blowback weapon, firing from open bolt and in full automatic only. The curved box magazine was inserted horizontally from the left, with ejection to the right. Barrel was enclosed into the tubular jacket, perforated for better cooling, and fitted with muzzle brake – compensator. The Type 100 submachine gun was equipped with carbine-style wooden stock. Paratrooper version of this weapon had a side-folding stock, with hinge located on the right side of the stock, just behind the trigger guard. Early Type 100 submachine guns were fitted with adjustable rear sights, 1944-model weapons had fixed rear sights.