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Rifle · SAAMI

.338 Winchester Magnum

.338 Win Mag

The most versatile dangerous-game cartridge available in standard-length actions.

Caliber
0.338″ · 8.585 mm
Introduced
1958
Case
Belted
Parent
.375 H&H Magnum
Primary use
Hunting, Big Game, Long Range
Status
Active
Velocity2,400–2,900 fps
Energy2,560–4,000 ft·lb
Typical grains200 · 225 · 250 gr
Identity
Introduced
1958
Type
Rifle
Origin
United States
Inventor
Winchester
Manufacturer
Winchester
Standard
SAAMI
Status
Active
Availability
Common
Build
Case capacity
91 gr H₂O
Twist (typical)
1:10
Primer
Large Rifle Magnum
Case type
Belted
Pressure & range
Max pressure
64,000 psi
Eff. range
500 yd
Max range
1500 yd
Recoil
20–28 ft·lb

Ballistics

Real trajectory computed from a representative load — Berger OTM Target 300 gr, 2,600 fps, BC 0.417 G7 · 100 yd zero.

overlay up to 2
RangeVelocityEnergyDrop (in)Drop (MOA)
0 yd26004501-1.5″—
100 yd249541440.0″0.0
200 yd23913809-4.1″-2.0
300 yd22913495-14.3″-4.5
400 yd21933202-31.1″-7.4
500 yd20972927-55.2″-10.5
600 yd20032671-87.1″-13.9
700 yd19112432-127.7″-17.4
800 yd18212208-177.9″-21.2

Point-mass G7/G1 drag model, standard atmosphere — within ~2% of reference solvers to 1000 yd; real barrels and conditions vary. Open in Ballistic Compare →

Performance

Best for HuntingBerger Hunting VLD300 gr · VLD Hunting · 2,600 fps · BC 0.417 G7Buy now →
Best for TargetBerger OTM Target300 gr · Hybrid OTM · 2,600 fps · BC 0.417 G7Buy now →

Buy links open .338 Winchester Magnum ammunition at Rivertown Munitions.

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
Measuremmin✓
Bullet ⌀8.590.338✓
Neck ⌀9.370.369✓
Shoulder ⌀12.470.491✓
Shoulder angle25°—✓
Base ⌀13.030.513✓
Rim ⌀13.510.532✓
Belt ⌀13.510.532~
Rim thickness1.270.050✓
Neck length8.380.330≈
Case length63.502.500✓
Overall length84.843.340✓

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. .338 Winchester Magnum is highlighted below.

Factory loads

In production — 348 active loads across 32 brands. Top 15 shown · see all 351 →.

BrandLoadGrainBulletFPSft·lbBC
HornadySuperformance SST185SST3,0803,8960.272 G7
HornadySuperformance GMX185GMX Lead Free3,0803,8960.443 G1
HornadyCustom185GMX3,0803,8960.443 G1
HornadySuperformance185SST3,0803,8960.272 G7
HornadyAmerican Whitetail Interlock SP200Interlock SP2,9603,8900.414 G1
HornadyCustom Interlock SP200Interlock SP2,9603,8900.414 G1
HornadyAmerican Whitetail200InterLock BTSP2,9603,8900.414 G1
HornadySuperformance SST225SST Polymer Tip2,9404,3180.300 G7
HornadyOutfitter GMX225GMX Solid Copper2,9404,3180.550 G1
HornadySuperformance225GMX2,9204,2590.550 G1
HornadyOutfitter225CX2,9004,2010.343 G7
DoubleTapHunting225AccuBond LR2,9004,2010.278 G7
HornadyPrecision Hunter230ELD-X2,8904,2650.327 G7
HornadySuperformance225SST2,8404,0290.300 G7
HornadySuperformance SST225SST2,8404,0290.300 G7

Velocities are manufacturer-stated (test-barrel). Discontinued loads dimmed.

Suitable powders

16 reloading powders listed for .338 Winchester Magnum, fastest to slowest. Cross-reference in the finder →

Accurate 4350Norma MRPS355Reloader 19Ramshot Big GameH4831SCAR 2213SCVihtavuori N160RS70Tubal 7000N165N565Alliant Reloader 22780Accurate MagProRamshot Magnum
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 Winchester Magnum

12 models in the database chamber .338 Winchester Magnum. Browse all →

Sako 90 Adventure .300 Win Mag 24-inchBergara B-14 Wilderness .375 H&H MagChristensen Arms Mesa 338 Win MagKimber Hunter .338 Win Mag 24-inchSavage Arms 110 Storm 375 H&H MagnumMossberg Patriot Cerakote 300 Win MagSavage Arms 110 Apex Hunter .375 Ruger 22-inchHenry Repeating Arms Long Ranger .338 Win Mag 24-inchSavage 110 Apex Storm XP .300 Win Mag 24-inchKimber Hunter 6.5 Creedmoor 22-inchSavage Arms 110 Bear Hunter .375 RugerKimber Hunter .308 Win 22-inch

Lineage

Immediate parent
.375 H&H Magnum
Direct descendants (0)
.375 Chatfield-Taylor
Family TreeOpen .338 Winchester Magnum in the interactive cartridge family tree↗

Connected reference

Loads351 factory loads for .338 Winchester Magnum↗Reloading16 suitable powders — cross-reference↗FirearmsFirearms in .338 Winchester Magnum↗ToolCompare ballistics↗

History

Introduced by Winchester in 1958 on the .375 H&H case. Immediately became the premium American big-game cartridge. Jack O'Connor and Elmer Keith debated it — O'Connor preferred his 7mm; Keith thought it perfect for heavy game.

FAQs

What twist rate does .338 Winchester Magnum use?
.338 Winchester Magnum typically uses a 1:10 twist rate.
What bullet diameter is .338 Winchester Magnum?
.338 Winchester Magnum uses a 0.338″ (8.585 mm) diameter bullet.
Is .338 Winchester Magnum still in production?
.338 Winchester Magnum is active; typical availability is common.
What is .338 Winchester Magnum used for?
.338 Winchester Magnum is primarily used for hunting, big game, long range.
What is .338 Winchester Magnum based on?
.338 Winchester Magnum is derived from the .375 H&H Magnum case.
What are the best powders for .338 Winchester Magnum?
Reloading powders commonly listed for .338 Winchester Magnum include Accurate 4350, Norma MRP, S355, Reloader 19, among 16 suitable options.

Sources & provenance

Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 348 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →