Skip to content
Lindcott Armory

Pistol · Obsolete

9mm Largo

Also known as 9mm Bergmann-Bayard · 9x23mm Largo · 9mm Bayard Long

Powerful 9mm cartridge adopted by Spain and Belgium in the early 20th century.

Caliber
0.3551″ · 9.02 mm
Introduced
1903
Case
Rimless
Parent
9mm Browning Long
Primary use
Military
Status
Discontinued

Buy this cartridge

Buy at Rivertown

Buying from Rivertown

Partner link

VelocityBeing verified
EnergyBeing verified
Typical grains124 · 130 gr
Identity
Introduced
1903
Type
Pistol
Origin
Belgium
Inventor
Theodore Bergmann
Manufacturer
Anciens Établissements Pieper (Belgium), various Spanish
Standard
Obsolete
Status
Discontinued
Availability
Collector
Build
Case capacity
15.5 gr H₂O
Twist (typical)
1:10
Primer
Small Pistol
Case type
Rimless
Pressure & range
Max pressure
34,084 psi
Eff. range
50 yd
Max range
100 yd
Recoil
4–6.5 ft·lb
Subsonic
Capable

Ballistics

Published velocity/energy data isn't available for 9mm Largo — an obsolete/collector cartridge. Parent case: 9mm Browning Long.

Performance

Best for Withheld until verified
Best for Withheld until verified
Dimensionscase measurements · scale drawing · size vs familiar rounds

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

SAAMI · approximate
Measuremmin
Bullet ⌀ 9.020.355 ·
Neck ⌀ 9.580.377 ~
Shoulder ⌀ n/a
Shoulder angle n/a
Base ⌀ 9.910.390 ·
Rim ⌀ 9.900.390 ·
Belt ⌀ n/a
Rim thickness 0.500.020 ~
Neck length n/a
Case length 23.000.906 ·
Overall length 33.501.319 ·

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. 9mm Largo is highlighted below.

Factory loads

Verification

Being verified

Advertised FPS, energy, and BC are withheld until loads clear verification.

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 9mm Largo

12 models in the database chamber 9mm Largo. Browse all →

Astra Astra 902 9mm Select FireVarious Spanish Star Model B 9mm Largo 5.1-inchAstra Model 400 9mm Largo 6.1-inchAstra Model 400Astra Model 400 9mm LargoAstra Astra Model 400 9mmAstra Astra 400 9mm Largo 6-inchAstra-Unceta Astra 400Astra Astra 400 9mm Largo 1921Bergmann Bergmann Syndicate M1910/21Astra Astra 400 9mm Largo 5.9-inchAstra 400

Lineage

Immediate parent

Most-direct documented parent is 9mm Bergmann-Bayard (not yet in the reference).

Family TreeOpen 9mm Largo in the interactive cartridge family tree

Connected reference

History

Originally developed for Theodore Bergmann's Model 1903 pistol, adopted by Belgium as the Bergmann-Bayard M1910. Spain adopted it as the standard military cartridge and chambered it in the Astra 400, 600, and Star Model B pistols for decades. Spanish forces used it through the Civil War and WWII. The cartridge remained in Spanish military service until the 1980s, with factory ammunition available until recently.

FAQs

What twist rate does 9mm Largo use?
9mm Largo typically uses a 1:10 twist rate.
What bullet diameter is 9mm Largo?
9mm Largo uses a 0.3551″ (9.02 mm) diameter bullet.
Is 9mm Largo still in production?
9mm Largo is discontinued; typical availability is collector.
What is 9mm Largo used for?
9mm Largo is primarily used for military.
What is 9mm Largo based on?
9mm Largo is derived from the 9mm Browning Long case.

Sources & provenance

Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 10 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →