Can You Shoot .308 Out of 7.62x51? Understanding the Subtle Differences
The short answer is: mostly, yes, but with caveats. The .308 Winchester and 7.62x51mm NATO cartridges are very similar, leading to much confusion. However, there are key differences that can impact safety and accuracy if you're not careful.
The Similarities: Why the Confusion?
Both .308 Winchester and 7.62x51mm NATO cartridges share the same basic projectile diameter (.308 inches) and are designed for similar applications. This similarity often leads people to believe they are interchangeable. They both deliver significant stopping power and are popular choices for hunting and long-range shooting.
The Key Differences: Where the Problems Arise
While the bullet diameter is similar, the critical differences lie in the case dimensions. The 7.62x51mm NATO cartridge has slightly larger case dimensions, meaning it's a little longer and wider. This might seem insignificant, but it impacts several aspects of firearm functionality:
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Headspace: This is the critical distance between the bolt face and the cartridge case head. A 7.62x51mm NATO cartridge fired in a .308 Winchester chamber can result in excessive pressure due to the larger case dimensions, potentially leading to catastrophic firearm failure. The chamber is simply not designed to handle the extra pressure.
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Chamber Pressure: The slightly larger case capacity of the 7.62x51mm NATO can result in higher chamber pressure. While many .308 rifles can handle this slightly higher pressure occasionally, consistent use can cause wear and tear, potentially leading to malfunctions or failure.
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Extractor and Ejector: While many firearms may function correctly, there is a slightly increased chance of issues with extraction or ejection due to the dimensional differences.
So, What's the Safe Practice?
The generally accepted practice is: Do not shoot 7.62x51mm NATO ammunition in a firearm chambered for .308 Winchester. While some .308 rifles might handle a few rounds without incident, the risk of damage or injury is simply too high to justify the practice.
Conversely, shooting .308 Winchester ammunition in a 7.62x51mm NATO chamber is generally considered safe. The extra space in the 7.62x51mm chamber allows for the slightly smaller .308 case to sit properly. However, this can sometimes lead to slightly lower accuracy.
The Importance of Checking Your Firearm's Manual
Always refer to your firearm's owner's manual before attempting to fire any ammunition. The manual will clearly state the recommended ammunition type. Ignoring this advice could have serious consequences.
Conclusion: Safety First
While the .308 Winchester and 7.62x51mm NATO cartridges might seem interchangeable at first glance, the subtle dimensional differences create a significant safety concern. Always prioritize safety and adhere to the manufacturer's recommendations for your specific firearm to avoid potentially dangerous and costly consequences. When in doubt, consult with a qualified firearms expert.
