The question of whether you can shoot 7.62x51 NATO ammunition in a rifle chambered for .308 Winchester is a common one, and the short answer is: generally no, and it's extremely dangerous to try. While the two cartridges appear similar and have nearly identical bullet diameters, there are crucial differences that make interchanging them incredibly risky.
Understanding the Differences Between 7.62x51 and .308 Winchester
Both 7.62x51 and .308 Winchester fire .308-caliber bullets, meaning the bullet's diameter is approximately .308 inches. However, the key differences lie in the cartridge case dimensions and chamber specifications.
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Case Dimensions: The 7.62x51 NATO cartridge case is slightly longer and larger in diameter than the .308 Winchester case. This seemingly small difference has significant consequences.
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Chamber Pressure: 7.62x51 NATO rounds are loaded to higher chamber pressures than .308 Winchester rounds. Firing a 7.62x51 round in a .308 Win chamber can result in catastrophic chamber failure. The higher pressure could cause the rifle to burst, leading to serious injury or death.
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Headspace: Headspace refers to the distance between the bolt face and the cartridge head. Even a slight mismatch in headspace can be dangerous. While some .308 Win chambers might appear to accommodate a 7.62x51 round, the higher pressure of the NATO round can overcome the headspace, leading to a catastrophic malfunction.
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Manufacturing Tolerances: The tolerances for manufacturing .308 Win and 7.62x51 NATO chambers are different. This contributes to the risk involved in trying to use interchangeable ammunition.
The Risks of Mixing 7.62x51 and .308 Winchester
Attempting to fire 7.62x51 in a .308 Win chamber is incredibly dangerous and could lead to:
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Chamber Rupture: The higher pressure of the 7.62x51 round can exceed the strength of the .308 Win chamber, causing it to rupture. This could result in gas escaping, damaging the firearm severely and causing injuries to the shooter and bystanders.
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Bolt Face Damage: The increased pressure could damage the bolt face, rendering the rifle unusable and potentially causing injury.
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Barrel Damage: High pressure can damage the barrel, leading to decreased accuracy or complete failure.
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Injury or Death: These are the worst-case scenarios, and sadly, they are very real possibilities when attempting this dangerous practice.
Case Study: While specific instances are difficult to compile due to safety concerns, anecdotal accounts from firearms forums and online communities consistently highlight the dangers of this interchange. Reports frequently describe blown-out actions, damaged barrels, and near-misses with serious injuries.
Why the Confusion?
The confusion stems from the fact that the bullet diameter is nearly identical. Many shooters assume that because the bullets are similar, the cartridges are interchangeable. However, this is a dangerous misconception. The subtle differences in cartridge case dimensions are the key factor.
What to Do Instead
If you own a .308 Win rifle and want to shoot 7.62x51, you will need a rifle that is specifically chambered for 7.62x51 NATO. Never attempt to use 7.62x51 NATO ammunition in a rifle chambered for .308 Winchester.
Conclusion: Safety First
Always prioritize safety when handling firearms and ammunition. Never compromise safety for convenience or out of ignorance. The risks involved in shooting 7.62x51 in a .308 Win chamber far outweigh any perceived benefits. Use only the ammunition your firearm is specifically designed for. If you have any questions about the ammunition you are using or your specific firearm, always consult a qualified gunsmith or firearms expert. Remember, firearm safety is paramount.