8×22mm Nambu

The 8×22mm Nambu is a semi-rimmed, bottleneck handgun cartridge introduced in Japan in 1904.

8×22mm Nambu
Japanese military pistol cartridge.
Type	Pistol Submachine gun
Place of origin	Japan
Service history
In service	1904–1945
Used by	Japan
Wars	World War I Second Sino-Japanese War World War II
Production history
Designer	Kijiro Nambu
Designed	1902
Specifications
Case type	Bottleneck semirimed
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
Ballistic performance
Bullet mass/type Velocity Energy 102 gr (7 g) FMJ 290 m/s (950 ft/s) 274 J (202 ft⋅lbf)
Test barrel length: 117 mm (4.61 in)

History

It was used in the Type A and B Nambus, Type 14 Nambu and Type 94 pistols, Tokyo Arsenal Model 1927, Type II machine pistol, Hino Komuro M1908 pistol and the Type 100 submachine gun. It uses 8.2 mm (.320") bullets. Power is relatively low, with military loads developing about 280 J (200 foot·pounds), comparable to the American .380 ACP and substantially weaker than contemporary military cartridges such as 9×19mm Parabellum, .45 ACP, and 7.62×25mm Tokarev.

Like almost all of the Imperial Japanese weapon designs of that era, production of 8 mm Nambu ammunition ceased after the end of World War II, as the weapons that fired it were removed from service. Some small-scale production (primarily using remanufactured brass) has occurred in the United States, but handloading is more common among owners of 8 mm Nambu pistols. New manufactured brass and copper plated lead bullets (.320") are available through HDS. Reloadable cases might be formed from .40" S&W, but this would require swaging the case heads down from .424" to .403" in a hydraulic press. A regular reloading press would quickly be ruined by this sort of operation.

The Japanese Army cartridges in 8 mm Nambu have no markings on the headstamp, unlike the Japanese Navy cartridges.

See also

• 8 mm caliber
• .32 ACP
• .32 NAA, a .380 ACP case necked-down to hold a .32 caliber bullet with the goal of improved ballistic performance over the .32 ACP.