7×20mm Nambu

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7×20mm Nambu
Place of originJapan
Service history
In service1903-1945
Used byJapan
WarsWorld War II
Production history
DesignerKijiro Nambu
ManufacturerType B Nambu Pistol 1. Tokyo Artillery Arsenal, Koishigawa, Tokyo 1903-1923 and 2. Tokyo Gas and Electric Co., Ltd., Tokyo 1923-1929. Was ammunition made in the same factories?
No. builtPistols - Possibly less than 6,500. 1. Tokyo c. 5,900 and 2. TGE c. 550. Number of 7x20mm rounds made is unknown but today they are a quite rare collector's item occasionally found in WW2 boxes of 50 rounds.
VariantsAt least 5, including a dummy. Variations mainly occur in type of bullet crimping, jacket type and rim thickness.
Case typeBottleneck rimless
Bullet diameter7.08 mm (0.279 in)
Neck diameter7.64 mm (0.301 in)
Shoulder diameter8.62 mm (0.339 in)
Base diameter8.91 mm (0.351 in)
Rim diameter9.11 mm (0.359 in)
Rim thickness0.98 mm (0.039 in)
Case length19.80 mm (0.780 in)
Overall length26.80 mm (1.055 in)
Primer typeSmall pistol
Ballistic performance
Bullet mass/type Velocity Energy
56 gr (4 g) FMJ 240 m/s (790 ft/s) 108 J (80 ft⋅lbf)
Test barrel length: 83 mm (3.25 in)

The 7×20mm Nambu is a rimless, bottleneck handgun cartridge designed in Japan for use in the Type B or "Baby" model Nambu pistol.[1] The cartridge is a scaled-down version of the 8×22mm Nambu used in all other Nambu pistol models. It has a muzzle energy more than a .25 ACP and close to the .32 ACP.[2][3][4]


  1. ^ Miller, David (2007). Fighting Men of World War II, Volume I: Axis Forces—Uniforms, Equipment, and Weapons. Stackpole Books. p. 276. ISBN 0-8117-0277-4.
  2. ^ "An Introduction to the Military Handguns of Imperial Japan". Gun Digest 2010. Krause Publications. 2009.
  3. ^ Dave Maccar (2016). Handguns & Handgun Shooting. p. 88. ISBN 1440246106.
  4. ^ T J Mullin (2015). 365 Guns You Must Shoot: The Most Sublime, Weird, and Outrageous Guns Ever. p. 167.

the Hand Cannons of Imperial Japan, Derby,H., 1981, Taylor Publishing Company, ISBN 0-940424-00-2 The Weapons Series no. 5 THE BABY NAMBU Japanese 7-mm. Pistol. Marsh, Roger, 1946, Pub. by the author.