What twist rate does .25 NAA use?

.25 NAA typically uses a 1:16 twist rate.

What bullet diameter is .25 NAA?

.25 NAA uses a 0.251″ (6.375 mm) diameter bullet.

Is .25 NAA still in production?

.25 NAA is active; typical availability is specialty.

What is .25 NAA used for?

.25 NAA is primarily used for self-defense.

Lindcott Armory

Pistol · SAAMI standardized

.25 NAA

Compact bottleneck pistol cartridge developed by North American Arms, necking down .32 ACP to 25 caliber.

Caliber: 0.251″ · 6.375 mm
Introduced: 2002
Case: Rimless
Parent: .32 H&R Magnum
Primary use: Self-Defense
Status: Active

Buy this cartridge

Buy at Rivertown

Buying from Rivertown

Partner link

VelocityBeing verified

EnergyBeing verified

Typical grains35 gr

Identity

Introduced: 2002
Type: Pistol
Origin: United States
Inventor: North American Arms / Corbon
Manufacturer: North American Arms
Standard: SAAMI standardized
Status: Active
Availability: Specialty

Build

Case capacity: 4.8 gr H₂O
Twist (typical): 1:16
Primer: Boxer Small Pistol
Case type: Rimless

Pressure & range

Max pressure: 23,000 psi
Eff. range: 50 yd
Recoil: 1.5–3 ft·lb
Subsonic: Capable

Introduced by North American Arms

Ballistics

Published velocity/energy data isn't available for .25 NAA.

Performance

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

Measure	mm	in	✓
Bullet ⌀	6.38	0.251	~
Neck ⌀	7.01	0.276	✓
Shoulder ⌀	8.46	0.333	✓
Shoulder angle	30°	—	✓
Base ⌀	8.56	0.337	✓
Rim ⌀	8.56	0.337	✓
Belt ⌀	n/a
Rim thickness	1.17	0.046	✓
Neck length	3.94	0.155	≈
Case length	18.92	0.745	✓
Overall length	24.38	0.960	✓

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. .25 NAA 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.

Powder $/lb Charge (gr) Bullet $/ea Primer $/ea Brass reuses Brass $/ea

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

Firearms chambered in .25 NAA

1 model in the database chamber .25 NAA. Browse all →

North American Arms Guardian

Lineage

Family TreeOpen .25 NAA in the interactive cartridge family tree

Connected reference

Loads19 factory loads for .25 NAA FirearmsFirearms in .25 NAA

History

Introduced around 2002 by North American Arms in partnership with CorBon. Created by necking down the .32 ACP case to accept .251" diameter bullets. Designed to give North American Arms mini-revolvers meaningful defensive velocity in an ultra-compact package.

FAQs

What twist rate does .25 NAA use?: .25 NAA typically uses a 1:16 twist rate.
What bullet diameter is .25 NAA?: .25 NAA uses a 0.251″ (6.375 mm) diameter bullet.
Is .25 NAA still in production?: .25 NAA is active; typical availability is specialty.
What is .25 NAA used for?: .25 NAA is primarily used for self-defense.

Sources & provenance

Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
Manufacturer North American Arms — .25 NAA · parent_cartridge
Reference Gun Digest Books — Cartridges of the World (Gun Digest Books, F. C. Barnes) · parent_cartridge

Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 19 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →