Rifle · Not SAAMI standardized
.400 Jeffery Nitro Express
W.J.
- Caliber
- 0.4098″ · 10.41 mm
- Introduced
- 1896
- Case
- Rimmed
- Parent
- .450/400 3" Black Powder Express
- Primary use
- Hunting
- Status
- Limited
- Introduced
- 1896
- Type
- Rifle
- Origin
- United Kingdom
- Inventor
- W.J. Jeffery & Co.
- Manufacturer
- W.J. Jeffery
- Standard
- Not SAAMI standardized
- Status
- Limited
- Availability
- Limited
- Case capacity
- 115 gr H₂O
- Twist (typical)
- 1:16
- Primer
- Boxer Large Rifle
- Case type
- Rimmed
- Max pressure
- 40,611 psi, CIP transducer
- Eff. range
- 150 yd
- Max range
- 5050 yd
- Recoil
- 60–80 ft·lb
Ballistics
Published velocity/energy data isn't available for .400 Jeffery Nitro Express. Parent case: .450/400 3" Black Powder Express.
Performance
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
CIP TDCC · verified| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 10.41 | 0.410 | ✓ |
| Neck ⌀ | 11.20 | 0.441 | ✓ |
| Shoulder ⌀ | 13.21 | 0.520 | ✓ |
| Shoulder angle | 15° | — | ✓ |
| Base ⌀ | 13.92 | 0.548 | ✓ |
| Rim ⌀ | 15.87 | 0.625 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.65 | 0.065 | ✓ |
| Neck length | 17.20 | 0.677 | ≈ |
| Case length | 76.20 | 3.000 | ✓ |
| Overall length | 95.25 | 3.750 | ✓ |
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. .400 Jeffery Nitro Express 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.
Lineage
History
W.J. Jeffery & Co. developed this rimless dangerous game cartridge around 1905. The .400 Jeffery fires 400-grain bullets at ~2,100 fps from bolt-action rifles, making it one of the few large-bore dangerous game rounds designed specifically for bolt-actions rather than double rifles. Still chambered by custom gunmakers.
FAQs
- What twist rate does .400 Jeffery Nitro Express use?
- .400 Jeffery Nitro Express typically uses a 1:16 twist rate.
- What bullet diameter is .400 Jeffery Nitro Express?
- .400 Jeffery Nitro Express uses a 0.4098″ (10.41 mm) diameter bullet.
- Is .400 Jeffery Nitro Express still in production?
- .400 Jeffery Nitro Express is limited; typical availability is limited.
- What is .400 Jeffery Nitro Express used for?
- .400 Jeffery Nitro Express is primarily used for hunting.
- What is .400 Jeffery Nitro Express based on?
- .400 Jeffery Nitro Express is derived from the .450/400 3" Black Powder Express case.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 8 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
