Will a .308 Shoot 7.62x51? Understanding Cartridge Compatibility
The short answer is: yes, but with important caveats. The .308 Winchester (7.62x51mm NATO) and 7.62x51mm are essentially the same cartridge, dimensionally speaking. However, subtle differences exist that can impact firearm function and safety.
What are the Differences?
While often used interchangeably, there are slight differences between .308 Winchester and 7.62x51mm NATO ammunition:
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Chamber Dimensions: The 7.62x51mm NATO specification allows for slightly larger chamber dimensions than the .308 Winchester specification. This means a rifle chambered for 7.62x51mm NATO can generally fire .308 Winchester ammunition safely. However, a rifle chambered for .308 Winchester should not fire 7.62x51mm NATO ammunition.
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Pressure: 7.62x51mm NATO ammunition is typically loaded to higher pressure than .308 Winchester ammunition. Firing high-pressure 7.62x51mm NATO ammo in a .308 Winchester chamber could lead to catastrophic chamber failure, resulting in serious injury or death.
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Case Head Dimensions: While minute, there are slight variations in the case head dimensions between the two cartridges. These variations, while typically insignificant for 7.62x51mm NATO chambers, could potentially become an issue in tightly-toleranced .308 Winchester chambers.
The Safety Implications
The key takeaway is that firing .308 Winchester in a 7.62x51mm NATO chamber is generally considered safe, while the opposite is not. The larger chamber dimensions of the 7.62x51mm NATO cartridge can accommodate the slightly smaller .308 Winchester cartridge without causing problems. However, the reverse is dangerous due to the potential for over-pressure and chamber failure.
Always consult your firearm's owner's manual to determine the appropriate ammunition. This manual should clearly state the recommended cartridge type.
Why the Confusion?
The confusion stems from the close relationship between the two cartridges. The .308 Winchester is essentially a commercial adaptation of the 7.62x51mm NATO cartridge. The subtle differences, while technically significant for firearm safety, are often overlooked in casual conversation.
Conclusion
While a firearm chambered for 7.62x51mm NATO will likely safely fire .308 Winchester ammunition, the reverse is incredibly dangerous. Always prioritize safety and adhere strictly to your firearm's owner's manual recommendations regarding ammunition type. Ignoring this advice could have dire consequences. When in doubt, consult a qualified firearms expert or gunsmith.
