Is the New 6.8x51 Military and Civilian Version More Powerful Than 7.62x51?
The 6.8x51 and 7.62x51 are two highly regarded military and civilian cartridges used around the world. Both offer unique advantages, and understanding their performance metrics can help shooters and military personnel make informed decisions. In this article, we will explore the differences in power between these two cartridges, focusing on their muzzle energy, velocities, and power retention over a range of distances.
Muzzle Energy and Velocity Comparison
At the muzzle, the 6.8x51 shows a decided advantage over the 7.62x51. This is due to the 6.8x51 cartridge's higher chamber pressure and use of proprietary powders developed by SIG. The 6.8x51 is available in two bullet weights: 130-grain and 140-grain. Currently, the 140-grain load delivers an impressive 3000 feet per second (FPS) at the muzzle, resulting in 2798 foot-pounds of energy.
In contrast, the 7.62x51 NATO cartridge, with its 147-grain bullet, has a muzzle velocity of 2790 FPS, providing 2591 foot-pounds of energy. The 80,000 PSI chamber pressure of the 6.8x51 is crucial for achieving these high velocities from a short barrel. Additionally, these high velocities and pressures are made possible through new proprietary powder blends developed by SIG specifically for this cartridge.
Power Retention Over Distance
The real advantage of the 6.8x51 becomes apparent at longer ranges due to its higher ballistic coefficient. While the 7.62x51 has less mass, it does not necessarily equate to better performance in the field. The 6.8x51 maintains its power and trajectory more effectively over longer distances, making it a preferred choice for military and hunting applications.
Proprietary Powder Blends and Chamber Pressure
The 6.8x51 leverages proprietary powder blends to achieve its high velocities, which are critical for performance in shorter barrels. This technology is a significant development, as it allows for precise control over powder usage and chamber pressures. The 80,000 PSI chamber pressure is a key factor in the 6.8x51's ability to generate the necessary velocities to maintain effectiveness in various applications.
Why Size Matters: The Lesson from the M14
While the 6.8x51 has less mass than the 7.62x51, it does not mean that it is inherently superior. The 7.62x51, despite its larger size, has the same kick, which is a lesson learned from experiences with the M14. The M14 suffered from user discomfort and recoil issues, leading to the development of the 5.56x45mm NATO. This example highlights that size is not always an indicator of performance, and the use of more powerful, yet manageable, cartridges is essential for user comfort and overall effectiveness.
Conclusion
In conclusion, the 6.8x51 and 7.62x51 cartridges each have unique strengths and weaknesses. The 6.8x51, with its higher muzzle energy, faster velocities, and better power retention over distance, offers significant advantages, especially for longer-range applications. However, the 7.62x51, despite its lower mass, has its own merits, particularly in terms of user comfort and ease of handling. Ultimately, the choice between these two cartridges depends on the specific needs and applications of the user.