Smaller companion to the 8mm Nambu, chambered in the 'Baby Nambu' Type B pistol issued to Japanese field-grade officers. Even less powerful than the already-marginal 8mm Nambu, the 7mm offered no meaningful advantage over a .32 ACP.
Type: Pistol
Introduced: 1902, Japan
Parent case: None
Standardization: None
Bullet diameter: 0.28" (7.11 mm)
Case length: 0.78" (19.81 mm)
Overall length: 1.06" (26.92 mm)
Max pressure: 25,000 PSI
Rim type: Rimless
Primer: Small Pistol
Typical twist rate: 1:10
Muzzle velocity: 1000–1050 fps
Muzzle energy: 122–134 ft-lbs
Effective range: 40 yd
Common bullet weights: 55 gr
Primary use: Military
Production status: Discontinued
Also known as: 7x20mm Nambu
History: Developed by Kijiro Nambu alongside the Type A 'Grandpa Nambu' pistol, which used 8mm. The Type B 'Baby Nambu' was a scaled-down version chambered in 7mm, issued to officers who wanted a smaller sidearm. Production was limited and the cartridge never achieved widespread adoption. Original specimens and ammunition are extremely rare collector items. The Baby Nambu is considered one of the most…
Notable firearms: Type B 'Baby Nambu' Pistol
Military use: Japan
Similar cartridges: 8mm Nambu, .32 ACP