The .338 Lapua Magnum is a powerful and versatile cartridge, prized for its long range accuracy and impressive stopping power. Understanding its dimensions is crucial for anyone using, reloading, or designing for this cartridge. This article provides a comprehensive look at the 338 Lapua Magnum cartridge dimensions, covering various aspects from its case dimensions to bullet specifications.
Case Dimensions of the 338 Lapua Magnum
The .338 Lapua Magnum's defining characteristic is its substantial case capacity, enabling it to propel heavy bullets at extremely high velocities. Let's break down the key dimensions:
Overall Length
The overall length of the cartridge is approximately 2.88 inches (73.15 mm). This includes the case, primer, and bullet. Variations exist depending on bullet length.
Case Length
The case length itself is approximately 2.36 inches (60 mm). This measurement is critical for proper chambering in a firearm. Variations may exist due to manufacturing tolerances.
Base Diameter
The base diameter of the .338 Lapua Magnum case is roughly 0.530 inches (13.46 mm). This large diameter contributes to the cartridge's robust construction and ability to handle high pressures.
Neck Diameter
The neck diameter, where the bullet is seated, measures approximately 0.348 inches (8.84 mm). This diameter is crucial for a secure bullet fit and accurate feeding. Improper neck sizing during reloading can lead to accuracy issues.
Shoulder Diameter
The shoulder diameter is approximately 0.472 inches (12 mm). This shoulder angle plays a critical role in case capacity and pressure buildup.
Rim Diameter
The rim diameter is 0.570 inches (14.48 mm). This is generally larger than many other magnum cartridges which aid in reliable extraction.
Bullet Specifications & Dimensions
The .338 Lapua Magnum is typically loaded with heavy bullets ranging from 250 grains to 300 grains. These heavy projectiles are key to its long-range capabilities. The bullet’s length greatly influences the overall cartridge length.
Common Bullet Weights and Lengths
| Bullet Weight (grains) | Approximate Bullet Length (inches) |
|---|---|
| 250 | 1.3 |
| 286 | 1.4 |
| 300 | 1.45 |
Note: These are approximate values and can vary slightly depending on the manufacturer.
It's crucial to remember that bullet length significantly impacts the overall cartridge length. Using a bullet longer than your rifle’s magazine or chamber will lead to feeding issues or potentially damaging your firearm.
Importance of Precise Dimensions
Maintaining precise dimensions is critical for the safe and reliable function of the .338 Lapua Magnum cartridge. Improperly sized cases or bullets can lead to:
- High pressure: Potentially causing dangerous conditions and firearm damage.
- Inaccurate shooting: Poor bullet seating and neck tension can lead to erratic flight paths.
- Feeding problems: Oversized cartridges may not chamber correctly, leading to malfunctions.
- Extraction issues: Cases that are too tight may be difficult to extract.
Case Studies & Examples
While specific case studies on dimension-related failures are often not publicly available due to safety concerns, anecdotal evidence from reloading forums frequently points towards problems arising from inconsistent dimensions due to improper reloading practices.
Conclusion
The .338 Lapua Magnum's dimensions contribute directly to its power and accuracy. Understanding these dimensions, both case and bullet, is fundamental for safe handling, reloading, and achieving optimal performance. Always consult your firearm manufacturer's specifications and follow safe reloading practices. Precise measurements and attention to detail are vital for the safe and effective use of this powerful cartridge.