The question of whether a .308 Winchester (7.62×51mm) can shoot 7.62 NATO ammunition is a common one, and the short answer is nuanced: generally, yes, but with important caveats. While both cartridges share the same basic dimensions, subtle differences can lead to issues if you're not careful.
The Similarities and Differences Between .308 Winchester and 7.62 NATO
Both the .308 Winchester and 7.62 NATO cartridges are similar in diameter (.308 inches) and overall length. However, several key distinctions exist:
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Chamber Pressure: 7.62 NATO operates at a significantly higher chamber pressure than the .308 Winchester. This difference is the primary reason why using the wrong ammunition can be dangerous.
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Case Dimensions: Though visually almost identical, there are minor dimensional variations in the case dimensions, particularly in the shoulder angle and case head. These seemingly slight differences could lead to problems.
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Ammunition Manufacturers' Specifications: While often interchangeable in practice, the manufacturers of each cartridge have different specifications and quality control measures. This can affect the consistency of performance and reliability.
The Risks of Firing 7.62 NATO in a .308 Winchester Rifle
Firing 7.62 NATO ammunition in a rifle chambered for .308 Winchester carries significant risks, potentially resulting in:
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Chamber Pressure Catastrophe: The higher chamber pressure of 7.62 NATO can exceed the design limits of a .308 Winchester chamber, leading to dangerous overpressure. This can cause catastrophic rifle failure, including:
- Barrel burst: The barrel could rupture, causing serious injury or death.
- Receiver damage: The receiver can crack or break.
- Bolt face failure: The bolt can fail under the increased pressure.
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Damage to the firearm: Even if a catastrophic failure doesn't occur, repeated firing of 7.62 NATO can cause gradual damage to the rifle's barrel, action, and other components, shortening its lifespan and reducing accuracy.
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Injury or Death: The potential for catastrophic failure highlights the most severe consequence: serious injury or death to the shooter or bystanders.
When it Might Seem Safe (But Isn't)
Some sources suggest that modern .308 Winchester rifles are often manufactured with slightly larger chambers to accommodate the variations between the two cartridges. However, this is not a guarantee. Relying on this assumption is risky and could result in serious consequences. Even if the round chambers and fires, the increased pressure can still cause damage over time.
Practical Advice: Stick to the Specified Cartridge
The safest and most reliable practice is to always use the ammunition specifically designed for your rifle's chambering. Never assume interchangeability. Check your firearm's owner's manual for the manufacturer's clear instructions on acceptable ammunition. Ignoring this advice is reckless and potentially fatal.
Conclusion: Safety First
While the .308 Winchester and 7.62 NATO cartridges bear a close resemblance, the differences in chamber pressure make using the wrong ammunition exceptionally dangerous. The risks of using 7.62 NATO in a .308 Winchester rifle far outweigh any perceived benefits. Prioritize firearm safety by adhering to the manufacturer's recommendations and using the correct ammunition. The potential consequences of ignoring this advice are simply too severe to risk.