Rifle · SAAMI
.338 Remington Ultra Magnum
The .338 caliber member of Remington's Ultra Mag family.
- Caliber
- 0.338″ · 8.585 mm
- Introduced
- 2002
- Case
- Rebated
- Parent
- .300 Remington Ultra Magnum
- Primary use
- Hunting
- Status
- Active
- Introduced
- 2002
- Type
- Rifle
- Origin
- United States
- Inventor
- Remington Arms
- Manufacturer
- Remington / Federal
- Standard
- SAAMI
- Status
- Active
- Availability
- Specialty
- Case capacity
- 115 gr H₂O
- Twist (typical)
- 1:10
- Primer
- Large Rifle Magnum
- Case type
- Rebated
- Max pressure
- 65,000 psi
- Eff. range
- 600 yd
- Max range
- 1500 yd
- Recoil
- 15–22 ft·lb
Ballistics
Published velocity/energy data isn't available for .338 Remington Ultra Magnum. Parent case: .300 Remington Ultra 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 · verified| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 8.59 | 0.338 | ✓ |
| Neck ⌀ | 9.42 | 0.371 | ✓ |
| Shoulder ⌀ | 13.36 | 0.526 | ✓ |
| Shoulder angle | 30° | — | ✓ |
| Base ⌀ | 13.97 | 0.550 | ✓ |
| Rim ⌀ | 13.56 | 0.534 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.27 | 0.050 | ✓ |
| Neck length | 8.38 | 0.330 | ≈ |
| Case length | 70.10 | 2.760 | ✓ |
| 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. .338 Remington Ultra Magnum is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Suitable powders
9 reloading powders listed for .338 Remington Ultra 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 .338 Remington Ultra Magnum
1 model in the database chamber .338 Remington Ultra Magnum. Browse all →
Lineage
Connected reference
History
Introduced in 2002 on the same rebated-rim Ultra Mag case as the .300 RUM. The .338 RUM filled the gap between .338 Winchester Magnum and the more exotic .338 Lapua Magnum — offering near-Lapua performance in a platform more accessible to hunters than the Lapua's military-derived bolt actions. Remington chambered the Model 700 in .338 RUM; Federal produced Vital-Shok ammunition. The .338 Lapua's growing commercial presence and the .338 Norma Magnum's introduction have squeezed the .338 RUM's market position, but Remington and Federal continue production.
FAQs
- What twist rate does .338 Remington Ultra Magnum use?
- .338 Remington Ultra Magnum typically uses a 1:10 twist rate.
- What bullet diameter is .338 Remington Ultra Magnum?
- .338 Remington Ultra Magnum uses a 0.338″ (8.585 mm) diameter bullet.
- Is .338 Remington Ultra Magnum still in production?
- .338 Remington Ultra Magnum is active; typical availability is specialty.
- What is .338 Remington Ultra Magnum used for?
- .338 Remington Ultra Magnum is primarily used for hunting.
- What is .338 Remington Ultra Magnum based on?
- .338 Remington Ultra Magnum is derived from the .300 Remington Ultra Magnum case.
- What are the best powders for .338 Remington Ultra Magnum?
- Reloading powders commonly listed for .338 Remington Ultra Magnum include N170, Reloader 25, Reloader 26, IMR 7977, among 9 suitable options.
Sources & provenance
- Standard SAAMI — SAAMI cartridge & chamber drawing — .338 Remington Ultra Magnum archived
- Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 15 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →