Rifle · SAAMI
.340 Weatherby Magnum
The most powerful .338 in a standard-length action for decades.
- Caliber
- 0.338″ · 8.585 mm
- Introduced
- 1962
- Case
- Belted
- Parent
- .375 H&H Magnum
- Primary use
- Big Game, Dangerous Game, Hunting
- Status
- Active
- Introduced
- 1962
- Type
- Rifle
- Origin
- United States
- Inventor
- Roy Weatherby
- Manufacturer
- Weatherby
- Standard
- SAAMI
- Status
- Active
- Availability
- Common
- Case capacity
- 99 gr H₂O
- Twist (typical)
- 1:10
- Primer
- Large Rifle Magnum
- Case type
- Belted
- Max pressure
- 63,800 psi
- Eff. range
- 500 yd
- Max range
- 1500 yd
- Recoil
- 30–42 ft·lb
Introduced by Weatherby
Ballistics
Published velocity/energy data isn't available for .340 Weatherby Magnum. Parent case: .375 H&H Magnum.
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 ⌀ | 8.59 | 0.338 | ✓ |
| Neck ⌀ | 9.30 | 0.366 | ✓ |
| Shoulder ⌀ | 12.57 | 0.495 | ✓ |
| Shoulder angle | — | — | |
| Base ⌀ | 13.00 | 0.512 | ✓ |
| Rim ⌀ | 13.50 | 0.531 | ✓ |
| Belt ⌀ | 13.50 | 0.531 | ✓ |
| Rim thickness | 1.24 | 0.049 | ✓ |
| Neck length | 8.64 | 0.340 | ≈ |
| Case length | 71.76 | 2.825 | ✓ |
| Overall length | 93.98 | 3.700 | ~ |
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. .340 Weatherby Magnum is highlighted below.
Missing a dimension for .340 Weatherby Magnum? 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.
Suitable powders
5 reloading powders listed for .340 Weatherby Magnum, fastest to slowest. Cross-reference in the finder →
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 .340 Weatherby Magnum
12 models in the database chamber .340 Weatherby Magnum. Browse all →
Lineage
Connected reference
History
Introduced in 1962 for hunters who wanted more than .338 Win Mag but didn't need the extreme dimensions of African express cartridges. Found success with Alaskan guides and hunters pursuing large bears and moose at extended ranges.
FAQs
- What twist rate does .340 Weatherby Magnum use?
- .340 Weatherby Magnum typically uses a 1:10 twist rate.
- What bullet diameter is .340 Weatherby Magnum?
- .340 Weatherby Magnum uses a 0.338″ (8.585 mm) diameter bullet.
- Is .340 Weatherby Magnum still in production?
- .340 Weatherby Magnum is active; typical availability is common.
- What is .340 Weatherby Magnum used for?
- .340 Weatherby Magnum is primarily used for big game, dangerous game, hunting.
- What is .340 Weatherby Magnum based on?
- .340 Weatherby Magnum is derived from the .375 H&H Magnum case.
- What are the best powders for .340 Weatherby Magnum?
- Reloading powders commonly listed for .340 Weatherby Magnum include Norma 204, Norma MRP, N170, Reloader 25, among 5 suitable options.
Sources & provenance
- Standard SAAMI — SAAMI cartridge & chamber drawing — .340 Weatherby Magnum
- Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
- Manufacturer Weatherby — Weatherby Ballistics Chart · grain_ballistics, representative_gun
- Manufacturer Choice Ammunition — .340 Weatherby Magnum Ammunition by Choice Ammunition · grain_ballistics, representative_gun
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 22 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →