Rifle · Wildcat
.400 Whelen
Wildcat built by necking the .30-06 Springfield to .40 caliber, accepting .405 Winchester bullets.
- Caliber
- 0.411″ · 10.439 mm
- Introduced
- 1987
- Case
- Rimless
- Parent
- .30-06 Springfield
- Primary use
- Hunting
- Status
- Limited
- Introduced
- 1987
- Type
- Rifle
- Origin
- United States
- Inventor
- Townsend Whelen
- Manufacturer
- Colonel Townsend Whelen
- Standard
- Wildcat
- Status
- Limited
- Availability
- Specialty
- Case capacity
- 70 gr H₂O
- Twist (typical)
- 1:12
- Primer
- Boxer Small Rifle
- Case type
- Rimless
- Max pressure
- 55,000 psi
- Eff. range
- 300 yd
- Recoil
- 40–55 ft·lb
Ballistics
Published velocity/energy data isn't available for .400 Whelen.
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 ⌀ | 10.44 | 0.411 | ~ |
| Neck ⌀ | 11.02 | 0.434 | ~ |
| Shoulder ⌀ | 11.61 | 0.457 | ~ |
| Shoulder angle | — | — | |
| Base ⌀ | 11.96 | 0.471 | ~ |
| Rim ⌀ | 12.01 | 0.473 | ~ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.24 | 0.049 | ~ |
| Neck length | — | — | |
| Case length | 63.25 | 2.490 | ~ |
| Overall length | 84.84 | 3.340 | ~ |
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 Whelen is highlighted below.
Missing a dimension for .400 Whelen? 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
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
Connected reference
History
A wildcat cartridge created by necking up the .30-06 Springfield case to .40 caliber. Developed by experimenters seeking an all-around North American big game cartridge. Ballistically similar to .400 Whelen but using readily available .30-06 parent brass. Never commercially produced.
FAQs
- What twist rate does .400 Whelen use?
- .400 Whelen typically uses a 1:12 twist rate.
- What bullet diameter is .400 Whelen?
- .400 Whelen uses a 0.411″ (10.439 mm) diameter bullet.
- Is .400 Whelen still in production?
- .400 Whelen is limited; typical availability is specialty.
- What is .400 Whelen used for?
- .400 Whelen is primarily used for hunting.
Sources & provenance
- Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
- Reference Wikipedia — .400 Whelen (pointer; cites Cartridges of the World / Whelen) · parent_cartridge
- Secondary Military Wiki (Fandom) — .30-06 Springfield Wildcat Cartridges (quotes Townsend Whelen) · parent_cartridge
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 21 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →