Pistol · SAAMI (not in current Z299)
.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 ACP
- Primary use
- Self-Defense
- Status
- Active
- Introduced
- 2002
- Type
- Pistol
- Origin
- United States
- Inventor
- J.B. Wood (25/32 JBW concept); developed by North American Arms with Cor-Bon
- Manufacturer
- North American Arms
- Standard
- SAAMI (not in current Z299)
- Status
- Active
- Availability
- Specialty
- Case capacity
- 9.75 gr H₂O
- Twist (typical)
- 1:16
- Primer
- Boxer Small Pistol
- Case type
- Rimless
- Max pressure
- 23,000 psi, SAAMI transducer
- Eff. range
- 50 yd
- Max range
- 1950 yd
- Recoil
- 0.65–0.84 ft·lb
- Subsonic
- Capable
Introduced by North American Arms
Ballistics
Published velocity/energy data isn't available for .25 NAA. Parent case: .32 ACP.
Performance
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
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 .25 NAA
Lineage
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.
- What is .25 NAA based on?
- .25 NAA is derived from the .32 ACP case.
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 →
