A Japanese Officer’s Pistol: the Baby Nambu

The Nambu Automatic Pistol Type B, or “Baby Nambu” as it is known in US collecting circles, is a scaled-down companion to the 1902 “Grandpa” Nambu pistol. It was intended as a private purchase option for officers who needed to carry a sidearm, but did not want or need a full size service pistol. It was chambered for the 7mm Nambu cartridge (roughly on par with .25ACP).

Despite its small size and light cartridge, the Baby Nambu copied the complete locking system of the larger Nambu, resulting in a quite expensive pistol. As a result, demand was slim, and only 6500 were manufactured between 1903 and 1929, when production ended. Most of these were made by the Tokyo Army Arsenal, although production did move to the TG&E company in about 1923 (presumably after the great Tokyo earthquake).


  1. “As a result, demand was slim, and only 6500 were manufactured between 1903 and 1929, when production ended. Most of these were made by the Tokyo Army Arsenal, although production did move to the TG&E company in about 1923 (presumably after the great Tokyo earthquake).”
    Description of 7mm Nambu cartridge in municion:
    if I understand correctly: 6000 pistols were made by Tokyo Arsenal and 550 by Tokyo Gas and Electric

  2. “7mm Nambu cartridge (roughly on par with .25ACP)”
    However, we should keep in mind that it was earlier than .25 Auto and in early days of automatic pistols no-one was sure right way, hence locking system might be understood.

    “manufactured between 1903 and 1929”
    Quite long – in 1929 it must be obvious that locking system for such cartridge is unnecessary and make it expensive.

    Small-caliber automatic pistols for officers was not only used in Japan, for example in Germany die Schmeisserpistole firing .25 Auto cartridge were used: http://unblinkingeye.com/Guns/HS25/hs25.html

    • 7mm Nambu is probably not a good thing to have in your innards. I suppose that if the bullet penetrated the victim’s skull the brain would be reduced to a jelly!

  3. I’m not so sure the 7mm round would be defined as being no more powerful than a .25 ACP.

    Ezell(Handguns of the World) credits the 7 x 19.7mm Nambu with a 56 grain bullet at 1100 F/S for 148 FPE. Smith (Small Arms of the World, 11th ed.) gives it 1050 and 137 FPE.

    Barnes (Cartridges of the World) states 56 grains at 1250 for 196 FPE.

    By comparison, they give the statistics for the 8 x 21mm Nambu as;

    Ezell; 102 gr. at 1067 for 257 FPE

    Smith: Same

    Barnes; 102 at 960 for 202 FPE.

    If you believe Barnes, the 7 x 19.7mm and 8 x 21mm rounds were roughly equivalent to each other in power, and both were in the same power class as the 9 x 20SR Browning (9mm Browning Long).

    If you believe Ezell and/or Smith, the 7mm was about equal to the “warmer” factory loadings of the 7.65 x 17mm Browning (.32 ACP). While the 8mm was more like the .38 Special revolver round in typical factory loadings of the day.

    I also question whether or not the 7mm actually needed a locked breech action. But I would say an officer armed with one was packing at least the equivalent of a .32 ACP, not a .25.



    • “I also question whether or not the 7mm actually needed a locked breech action.”
      But only Nambu in late 19th/early 20th century used locking mechanism where we would judge it unnecessary. For other example see Roth-Sauer automatic pistol:
      It fired own 7.65 mm cartridge weaker that .32 Auto (7,65 Browning)

  4. ALERT ballistics data discrepancy!

    You and English Wikipedia’s source¹ give .25 ACP class ballistics, but Teri at Nambuworld says “Ballistically the 7mm Nambu (left) is comparable to the .32ACP” (http://www.nambuworld.com/originalcollectibleammo.htm). The source² of German Wikipedia agrees with her; numbers are 55 grains @ 1050 fps for ME of 135 ft•lbf.

    This is a fairly major difference (unlike, say, the differences in 8mm Nambu ballistics in different sources), so either some of the numbers must be wrong or the Japanese significantly improved the loading during production. They did do that with the 8mm Nambu (thus the different numbers), albeit for a lesser extent, so it could very well be that they did it with the 7mm Nambu as well. The locked breech action would have made it possible.

    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.
    ²Jakob H. Brandt: Handbuch der Pistolen- und Revolverpatronen = Manual of Pistol and Revolver Cartridges. Überarbeitete und ergänzte Neuauflage. Journal-Verlag Schwend, Schwäbisch Hall 1998, ISBN 3-936632-10-3.

        • “That would most certainly penetrate a dinner table”
          Data for TK (6,35mm) automatic pistol:
          distance 10 (шаг, 1 шаг = 71,12 cm)
          bullet fully penetrated 4 pine planks and stay clogged in 5th.
          Each plank thickness is 17 mm, space between each planks is 7 mm.

  5. Ballistically the 7mm Nambu (left) is comparable to the .32ACP
    I has idea.
    “Baby” Nambu is Nambu’s answer to FN Browning M1900.
    If “Baby” Nambu first prototype is later than day when FN Browning M1900 entered market following hypothesis might be true:
    Nambu become aware of FN automatic pistol commercial success, so chose to react, but he was unable to examine example of FN Browning M1900 and what he have was ballistic data for .32 Auto and data like dimensions (length,width,height) and mass
    Notice that both FN Browning 1900 and “Baby” Nambu shares similar overall length (~170 mm) and mass unloaded (FN: 625 g, Nambu: 650 g) and identical capacity (7)

  6. Back in the early 60’s a friend that worked in a gun shop tried to get me to but a pair of Nambu pistols. I thought at the time that they were too ugly to buy. As I recall they were a Papa and a baby and as I recall they were consecutively serial numbered. Was that a possibility?

  7. Bill Ruger thought enough of this little pistol to make two copies of it in 22lr to bad he decided not to market it. I’d love to have a original or any Nambu for that matter.

    • Well, the old reliable Ruger Standard Auto in .22LR closely follows the Nambu in layout. People just think of it as more like the P.08 Parabellum because of the similarities between the designers’ names; “Ruger” and “Luger”.

      Of the two, I’d rather have the Ruger, and not just because of the caliber. The Ruger is probably more reliable (allowing for the chronic problem of feeding the rimmed .22 round from any kind of box magazine),and as involved as its stripping procedure is, it’s still simpler than that of any of Nambu’s pistol designs.



  8. Anyone have a reliable starting load for the 7mm Baby Nambu round? I have my own custom Lee 6 cavity mould for a 55gr bullet in linotype matching the original very closely in shape, and have made my own cases out of M1 Carbine brass.
    (Hi Teri.)

  9. My Baby Nambu shoots quite well. At 15 yards I was able to keep all shots inside a 7″ spread. Pleasant and comfortable to shoot using some expensive new ammo. It feels like a .32 recoil wise.- Dave.

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