Japanese military pistol cartridge.
|Place of origin||Japan|
World War I
Second Sino-Japanese War
World War II
|Case type||Bottleneck semirimmed|
|Bullet diameter||8.13 mm (0.320 in)|
|Neck diameter||8.71 mm (0.343 in)|
|Shoulder diameter||10.00 mm (0.394 in)|
|Base diameter||10.23 mm (0.403 in)|
|Rim diameter||10.50 mm (0.413 in)|
|Rim thickness||0.92 mm (0.036 in)|
|Case length||21.43 mm (0.844 in)|
|Overall length||31.56 mm (1.243 in)|
|Primer type||small pistol|
|Test barrel length: 117 mm (4.61 in)|
The 8×22mm Nambu is a semi-rimmed, bottleneck handgun cartridge introduced in Imperial Japan in 1904, used in the Type 100 submachine gun and Nambu pistol. The 8x22mm round was used during the Pacific War and Second Sino-Japanese War, where its weakness compared to other handgun rounds such as the .45 ACP was noted. Production of the cartridge ceased after the war.
Towards the end of the 19th century, certain semi-automatic pistol designs began to see production, such as the Borchardt C-93 and Mauser C96. Japan, in the midst of the Meiji Restoration, was keen to not fall behind when it came to military technology, and devised a replacement for their Type 26 revolver. By 1902, the first Nambu pistol was developed, which was chambered in the 8x22mm Nambu round, and was promptly adopted as the Japanese service pistol.
The 8x22mm Nambu round was used in the Nambu pistols, which were first used during the Russo-Japanese War. However, due to the short length of the war, and the fact it was mostly fought at sea, not on land, it is generally considered an unimportant event, and little information about the Nambu pistols from this time is available. Major usage didn't begin until the Second Sino-Japanese War and Pacific War, during which time, the Type 100 submachine gun was created, which also fired 8x22mm Nambu. Overall, neither the Type 100 nor Nambu pistols reached impressive production numbers, as the Japanese arms industry was lackluster compared to other nations, and their weapons were not exported. By the war's end in 1945, around 400,000 Nambu pistols and 8,500 Type 100s had been produced. During this same time, the United States had produced a million M1911 pistols, 1.75 million Thompson submachine guns, and 650,000 M3 submachine guns, all in .45 ACP, their own handgun cartridge.
After the war, the 8x22mm round was mostly forgotten. Though there are isolated reports of usage by the Viet Cong during the opening stages of the Vietnam War, overall, there was no demand to keep the 8x22mm round afloat, and the post-war Japan Self-Defense Forces swiftly replaced it with the 9×19mm Parabellum, which during World War II was already in use in the United Kingdom and Germany. The JSDF replaced the Nambu pistol and Type 100 with the SIG Sauer P220 and Minebea PM-9, respectively.
However, because of the rarity and historical impact of the 8x22mm Nambu, it has become popular among collectors. A box of just 15 rounds was sold in 2009 for $250.
The 8x22mm Nambu round quickly gained notoriety for its weakness, especially in comparison to other handgun cartridges that were being fielded by other nations at the same time - it had half the muzzle energy of the 9×19mm Parabellum and even less than that of the 7.62×25mm Tokarev. The power of the round is approximately equal to that of the .32 ACP (7.65×17mm). For reference, tests conducted by the United States around 1904 concluded that no handgun cartridge below .45 ACP would have appropriate stopping power to be effective in military use.