Rifle · SAAMI
.300 H&H Magnum
The grandfather of all belted magnums.
- Caliber
- 0.3079″ · 7.82 mm
- Introduced
- 1925
- Case
- Belted
- Parent
- .375 H&H Magnum
- Primary use
- Hunting, Big Game
- Status
- Active
- Introduced
- 1925
- Type
- Rifle
- Origin
- United Kingdom
- Inventor
- Holland & Holland
- Manufacturer
- Holland & Holland
- Standard
- SAAMI
- Status
- Active
- Availability
- Common
- Case capacity
- 95 gr H₂O
- Twist (typical)
- 1:10
- Primer
- Large Rifle Magnum
- Case type
- Belted
- Max pressure
- 58,000 psi
- Eff. range
- 600 yd
- Max range
- 1500 yd
- Recoil
- 25–35 ft·lb
Introduced by Holland & Holland
Ballistics
Published velocity/energy data isn't available for .300 H&H 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 ⌀ | 8.59 | 0.338 | ✓ |
| Shoulder ⌀ | 11.43 | 0.450 | ✓ |
| Shoulder angle | 8.5° | — | ✓ |
| Base ⌀ | 13.03 | 0.513 | ✓ |
| Rim ⌀ | 13.51 | 0.532 | ✓ |
| Belt ⌀ | 13.56 | 0.534 | ~ |
| Rim thickness | 1.27 | 0.050 | ✓ |
| Neck length | 9.43 | 0.371 | ≈ |
| Case length | 72.39 | 2.850 | ✓ |
| Overall length | 91.44 | 3.600 | ✓ |
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 H&H Magnum is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Suitable powders
12 reloading powders listed for .300 H&H 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 H&H Magnum
12 models in the database chamber .300 H&H Magnum. Browse all →
Lineage
Connected reference
History
Holland & Holland introduced it in 1925 as the 'Super .30.' Won the 1935 Wimbledon Cup — America's premier long-range rifle match — fired by American Ben Comfort in a Mauser action. This victory introduced American shooters to the belted magnum concept. Winchester commercialized it in 1925. The belt was originally a headspacing device for double rifles.
FAQs
- What twist rate does .300 H&H Magnum use?
- .300 H&H Magnum typically uses a 1:10 twist rate.
- What bullet diameter is .300 H&H Magnum?
- .300 H&H Magnum uses a 0.3079″ (7.82 mm) diameter bullet.
- Is .300 H&H Magnum still in production?
- .300 H&H Magnum is active; typical availability is common.
- What is .300 H&H Magnum used for?
- .300 H&H Magnum is primarily used for hunting, big game.
- What is .300 H&H Magnum based on?
- .300 H&H Magnum is derived from the .375 H&H Magnum case.
- What are the best powders for .300 H&H Magnum?
- Reloading powders commonly listed for .300 H&H Magnum include N550, N560, Norma MRP, Vihtavuori N150, among 12 suitable options.
Sources & provenance
- Standard SAAMI — SAAMI cartridge & chamber drawing — .300 H&H 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 13 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →