Pistol · Obsolete

7mm Nambu

7x20mm Nambu

Smaller companion to the 8mm Nambu, chambered in the 'Baby Nambu' Type B pistol issued to Japanese field-grade officers.

Caliber
0.2787″ · 7.08 mm
Introduced
1902
Case
Rimless
Primary use
Military
Status
Discontinued
Velocity1,000–1,050 fps
Energy122–134 ft·lb
Typical grains102 gr
Identity
Introduced
1902
Type
Pistol
Origin
Japan
Inventor
Kijiro Nambu
Manufacturer
Tokyo Arsenal
Standard
Obsolete
Status
Discontinued
Availability
Antique
Build
Case capacity
9.5 gr H₂O
Twist (typical)
1:10
Primer
Small Pistol
Case type
Rimless
Pressure & range
Max pressure
25,000 psi
Eff. range
25 yd
Max range
100 yd
Recoil
2–4 ft·lb
Subsonic
Capable

Ballistics

Representative trajectory · 25 yd zero0–200 yd
25 yd · zero0″−55″55″ drop @ 200 yd0100200Open in Ballistic Compare ↗
Parent case

Representative trajectory — modeled from a single velocity input (no published BC for this cartridge yet).

Dimensionscase measurements · scale drawing · size vs familiar rounds

Case dimensions — the scale drawing at the top of the page is built from these.

Wikipedia · approximate
Measuremmin
Bullet ⌀7.080.279~
Neck ⌀7.640.301
Shoulder ⌀8.620.339
Shoulder angle
Base ⌀8.910.351
Rim ⌀9.110.359
Belt ⌀n/a
Rim thickness0.980.039
Neck length
Case length19.800.780
Overall length26.801.055

Size vs familiar rounds

Drawn at true 1:1 — every case is accurate relative to the others. Absolute size depends on your screen's pixel density, so measuring one against a real ruler may be off. 7mm Nambu is highlighted below.

Missing a dimension for 7mm Nambu? Some case measurements aren't in a published SAAMI/CIP drawing yet. Have a factory or reamer print? Send it → — verified hard-to-find data earns a free Lindcott sticker.

Factory loads

In production — 5 active loads across 4 brands. Top 15 shown · see all 19 →.

BrandLoadGrainBulletFPSft·lbBC
FiocchiFMJ102FMJ1,050250
Graf & SonsFMJ Reproduction102FMJ1,050250
Graf & SonsFMJ 102gr102FMJ985220
BertramFMJ Reproduction 102gr102FMJ985220
Buffalo ArmsFMJ Reproduction102FMJ985220
Buffalo ArmsCustom56FMJ1,148164
WolfFMJ56FMJ1,148164
Sellier & BellotSP56FMJ1,148164
NormaClassic56FMJ1,148164
PPUStandard56FMJ1,148164
RWSClassic56FMJ1,148164
KynochClassic56FMJ1,148164
ArmscorStandard56FMJ1,148164
Old Western ScroungerOWS Heritage56FMJ1,070142
Kokura ArsenalFMJ Ball102FMJ1,050250

Velocities are manufacturer-stated (test-barrel). Discontinued loads dimmed.

Reloading costestimate cost per round vs factory

Estimate your cost per round and how it compares to factory. Inputs are yours — nothing is stored.

Cost estimate only — not load data. Charge weight is your input; follow published manuals for safe charges.

Firearms chambered in 7mm Nambu

1 model in the database chamber 7mm Nambu. Browse all →

Various Japanese Arsenals Baby Nambu (Type 10)

Connected reference

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 beautiful Japanese pistol designs.

FAQs

What twist rate does 7mm Nambu use?
7mm Nambu typically uses a 1:10 twist rate.
What bullet diameter is 7mm Nambu?
7mm Nambu uses a 0.2787″ (7.08 mm) diameter bullet.
Is 7mm Nambu still in production?
7mm Nambu is discontinued; typical availability is antique.
What is 7mm Nambu used for?
7mm Nambu is primarily used for military.

Sources & provenance

Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 5 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →