Rifle · SAAMI
.300 Winchester Magnum
Popular magnum for long-range shooting and large game hunting.
- Caliber
- 0.308″ · 7.823 mm
- Introduced
- 1963
- Case
- Belted
- Parent
- .375 H&H Magnum
- Primary use
- Hunting, Military, Target
- Status
- Active
- Introduced
- 1963
- Type
- Rifle
- Origin
- United States
- Inventor
- Winchester
- Manufacturer
- Winchester Ammunition
- Standard
- SAAMI
- Status
- Active
- Availability
- Abundant
- Case capacity
- 93.8 gr H₂O
- Twist (typical)
- 1:10
- Primer
- Large Rifle Magnum
- Case type
- Belted
- Max pressure
- 64,000 psi, SAAMI transducer
- Eff. range
- 1200 yd
- Max range
- 5000 yd
- Recoil
- 25–38 ft·lb
Introduced by Winchester Ammunition
Ballistics
Published velocity/energy data isn't available for .300 Winchester 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.
CIP TDCC · verified| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 7.82 | 0.308 | ✓ |
| Neck ⌀ | 8.63 | 0.340 | ✓ |
| Shoulder ⌀ | 12.42 | 0.489 | ✓ |
| Shoulder angle | 25° | — | ✓ |
| Base ⌀ | 13.03 | 0.513 | ✓ |
| Rim ⌀ | 13.51 | 0.532 | ✓ |
| Belt ⌀ | 13.51 | 0.532 | ✓ |
| Rim thickness | 1.27 | 0.050 | ✓ |
| Neck length | 6.70 | 0.264 | ≈ |
| Case length | 66.55 | 2.620 | ✓ |
| 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. .300 Winchester Magnum is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Suitable powders
38 reloading powders listed for .300 Winchester 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 .300 Winchester Magnum
Lineage
Connected reference
History
Introduced by Winchester in 1963 as part of their magnum lineup. Quickly became most popular .30 magnum. Adopted by military snipers in 1990s as improvement over .308.
FAQs
- What twist rate does .300 Winchester Magnum use?
- .300 Winchester Magnum typically uses a 1:10 twist rate.
- What bullet diameter is .300 Winchester Magnum?
- .300 Winchester Magnum uses a 0.308″ (7.823 mm) diameter bullet.
- Is .300 Winchester Magnum still in production?
- .300 Winchester Magnum is active; typical availability is abundant.
- What is .300 Winchester Magnum used for?
- .300 Winchester Magnum is primarily used for hunting, military, target.
- What is .300 Winchester Magnum based on?
- .300 Winchester Magnum is derived from the .375 H&H Magnum case.
- What are the best powders for .300 Winchester Magnum?
- Reloading powders commonly listed for .300 Winchester Magnum include N550, Superperformance, N555, Vihtavuori N140, among 38 suitable options.
Sources & provenance
- Standard SAAMI — SAAMI cartridge & chamber drawing — .300 Winchester Magnum archived
- Standard C.I.P. — C.I.P. TDCC — Tables of Dimensions of Cartridges and Chambers
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 280 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
