.338 Lapua Magnum Cartridge Guide

Long Range Only

DISCLAIMER: This guide is for informational purposes only. Handloading data from individual rifles is not a starting load and may be above published data for your exact components. Brass capacity, chamber dimensions, freebore, seating depth, primer, powder lot, barrel and temperature can materially change pressure. Always consult current published data, begin below any listed charge, and work up carefully in your own rifle. USE AT YOUR OWN RISK.

The .338 Lapua Magnum is a purpose-built, high-performance .338-caliber cartridge designed to bridge the gap between traditional magnum rifle cartridges and the much larger .50 BMG. It combines a large, beltless case with heavy, high-BC bullets and has become one of the most recognized long-range cartridges in military, competition and hunting use.

For the long-range hunter, the .338 Lapua offers something smaller cartridges cannot completely duplicate: high retained energy, excellent wind performance with 250- to 300-grain bullets, and enough case capacity to drive those bullets at useful velocity without requiring an extreme-length case.

It is not a light-recoiling or inexpensive cartridge to shoot. It requires a large action, substantial barrel shank and bolt face, burns roughly 85 to 100 grains of slow powder depending on the combination, and benefits greatly from an effective muzzle brake or suppressor. But when the application calls for a true heavy long-range cartridge, the .338 Lapua Magnum remains one of the benchmarks.

History Of The .338 Lapua Magnum

The roots of the .338 Lapua Magnum go back to the early 1980s and the development of the .338/416 for a U.S. military long-range rifle project. The goal was to launch a 250-grain .338 bullet at approximately 3,000 fps and provide substantially more reach and penetration than the .300 Winchester Magnum while remaining far more portable than a .50 BMG system.

Early development used cases based on the .416 Rigby family, but the original case construction was not suitable for the pressures required. Lapua became involved in the project and redesigned the case, strengthening the web and surrounding structure to withstand the higher operating pressure.

Lapua completed early bullets and cases during the mid-1980s. The cartridge evolved from the .338/416 into the standardized .338 Lapua Magnum. The first test lot of .338 Lapua Magnum ammunition was produced in 1988, and C.I.P. approval followed in 1989.

Since then, the cartridge has been adopted in military precision rifles around the world and has also become established in civilian long-range competition, ELR shooting and long-range hunting.

Where The .338 Lapua Fits

The .338 Lapua is considerably larger than cartridges such as the .300 Winchester Magnum and .300 PRC, but it is still much smaller and more practical in a sporting rifle than the .50 BMG.

Its advantage is not simply muzzle velocity. The cartridge can launch bullets in the 250- to 300-grain range with extremely high ballistic coefficients. The combination of mass, BC and useful muzzle velocity provides excellent retained velocity and energy at long range.

For deer-sized game at ordinary hunting distances, the .338 Lapua is far more cartridge than is required. Its strengths become more relevant when the rifle is intended for large game, very long distances, severe wind conditions, or dual-purpose hunting and ELR use.

.338 Lapua Versus .300 PRC

The .300 PRC is one of the most logical modern comparisons. It can launch excellent .30-caliber bullets with less recoil, less powder, lighter rifles and lower component cost.

For most long-range hunting applications, the .300 PRC is easier to shoot well and more economical to practice with. The .338 Lapua begins to separate itself when the shooter wants the additional mass and BC of 285- to 300-grain .338 bullets. At extended range, those projectiles retain substantial energy and can perform very well in wind.

Standardization, Chamber And Freebore

Unlike many large long-range wildcats, the .338 Lapua Magnum is standardized. C.I.P. approved the cartridge in 1989, and SAAMI also publishes a .338 Lapua Magnum cartridge and chamber drawing.

Factory rifles, match chambers and custom reamers can still differ in freebore, neck dimensions and magazine length. The heavy bullets commonly used in this cartridge are long, and seating depth can materially affect usable case volume and pressure.

• Your actual chamber and freebore
• Maximum cartridge overall length to the lands with the intended bullet
• Magazine-length limitation
• Brass manufacturer and case capacity
• Primer type
• Barrel length and twist rate

Action And Rifle Considerations

The .338 Lapua requires a true magnum-length action designed for its large case head and cartridge diameter. Bolt diameter, extractor design, magazine dimensions and feed geometry all need to be appropriate for the cartridge.

Rifle weight also matters. A very light .338 Lapua can be built, but recoil and torque make it more difficult to shoot consistently. A quality muzzle brake makes an enormous difference. Suppressors can also reduce recoil and blast, but the suppressor must be rated appropriately for the cartridge and barrel length.

Brass

Lapua brass has long been the reference standard for the cartridge and appears repeatedly in the Long Range Only data. Good brass life is possible when loads are kept within sensible pressure, but changing brass brands can alter usable case volume enough to change pressure. Reduce the load and work back up when changing brass.

Bullet Selection

250-Grain Class

The cartridge was originally developed around a 250-grain projectile. These bullets can generally be driven faster than the 285- and 300-grain bullets, produce a flatter initial trajectory and reduce recoil somewhat.

270- to 285-Grain Class

The 270- to 285-grain class is an excellent middle ground. These bullets provide very high BC while retaining more velocity than the heaviest 300-grain offerings.

300-Grain Class

The 300-grain class is where the .338 Lapua is most often used for maximum long-range performance. Berger 300-grain bullets, Sierra 300-grain MatchKings and similar projectiles provide excellent BC and retained energy. They also require appropriate twist rate, throat geometry and magazine length.

Powder Selection

H1000: One of the most useful powders for the cartridge, with successful loads using both 285- and 300-grain bullets.

Retumbo: Another excellent .338 Lapua powder, especially with heavier bullets.

Reloder 33: Well suited to the case capacity of the .338 Lapua and capable of excellent velocity with 300-grain bullets.

Vihtavuori N570: A strong choice for heavy-bullet .338 Lapua loads when very slow burn rate and good loading density are desired.

Primer Selection

The .338 Lapua burns a large charge of slow powder, and magnum primers are the normal choice. Federal 215 and 215M primers appear repeatedly in the Long Range Only data. Primer substitution can change pressure, ignition characteristics and extreme spread, so reduce the charge and work back up when changing primers.

Barrel Length

The rifles in the collected data range from approximately 26 to 30 inches, with 26- to 28-inch barrels being particularly common. For a hunting rifle, 26 inches is a practical compromise. For a dedicated ELR or target rifle, 28 to 30 inches can take better advantage of the cartridge.

Twist Rate

Traditional .338 Lapua rifles have often used twists near 1:10, but the modern trend toward long 285- and 300-grain bullets makes faster twists attractive. For a new rifle specifically intended for modern 300-grain bullets, a 1:9-class twist deserves strong consideration.

Expected Performance

These are representative performance ranges, not velocity targets.

Representative Load Data

The following loads are examples from individual rifles. They are not starting loads. Reduce charges and work up carefully in your own rifle.

Accuracy

The .338 Lapua has a well-earned reputation for accuracy despite its size and recoil. The Long Range Only data includes factory rifles producing half-MOA-class accuracy and better, as well as custom or well-tuned combinations repeatedly shooting in the quarter- to one-third-MOA range.

Several contributors reported excellent performance at 400 yards, 600 yards, one mile and beyond. That is more meaningful for this cartridge than a single small group at 100 yards.

Hunting Performance

The .338 Lapua is a powerful hunting cartridge and should be paired with a bullet appropriate for the animal and expected impact velocity. The Long Range Only data includes successful use on antelope, deer and elk.

The cartridge provides enormous retained energy, but energy alone does not guarantee good terminal performance. Bullet construction and impact velocity remain critical.

Recoil And Shootability

Recoil is the largest practical disadvantage of the .338 Lapua. The shooter needs enough rifle weight, a good stock fit and an effective brake or suppressor to manage recoil and torque. For most hunters, a slightly heavier rifle that can be shot well will outperform an ultralight .338 Lapua in real field conditions.

Brass Life And Pressure

The .338 Lapua can provide very good brass life when pressures are sensible. Watch for sticky bolt lift, ejector marks, heavy extraction, excessive case-head growth and loosening primer pockets. If a load suddenly gains more velocity than expected, treat that as information rather than a bonus.

Reloading Dies And Case Preparation

The .338 Lapua is a standardized cartridge, so die selection is considerably simpler than with a wildcat. A high-quality full-length sizing die and micrometer seating die are ideal. Bushing dies can also work very well when the handloader wants direct control over neck tension.

Advantages Of The .338 Lapua Magnum

• Excellent performance with very high-BC 250- to 300-grain bullets
• Outstanding retained velocity and energy
• Excellent long-range and ELR capability
• Strong wind performance
• Standardized cartridge with broad rifle and component support
• Excellent quality brass available
• Very good accuracy potential
• Proven military, target and hunting history

Disadvantages Of The .338 Lapua Magnum

• Substantial recoil
• Large and heavy rifles
• High powder consumption
• Expensive bullets and brass
• Requires a true .338 Lapua-size action and bolt face
• Muzzle blast is significant
• More cartridge than most hunting situations require
• Practice cost is substantially higher than smaller long-range cartridges

Conclusion

The .338 Lapua Magnum earned its reputation because it solves a real ballistic problem. It can launch extremely high-BC .338 bullets at useful velocity from a rifle that remains far more portable than a .50-caliber system.

For most hunters, it is not necessary. A .300 PRC, .300 Winchester Magnum or similar cartridge is easier to carry, cheaper to shoot and easier to manage. But when the goal is heavy-bullet performance at truly extended range, the .338 Lapua remains difficult to dismiss.

The cartridge works particularly well with 285- and 300-grain bullets, slow powders such as H1000, Retumbo, Reloder 33 and N570, magnum primers, and barrels in roughly the 26- to 30-inch range.