The question, "Will a .308 shoot 7.62x51?" is a common one, and the short answer is: generally no, and it's incredibly dangerous to try. While the two cartridges look similar, there are crucial differences that make using a .308 Winchester chamber in a 7.62x51 NATO rifle extremely risky.
The Subtle but Significant Differences Between .308 Winchester and 7.62x51 NATO
Both .308 Winchester and 7.62x51 NATO are commonly referred to as ".30 caliber" rounds and have similar dimensions, leading to the confusion. However, key distinctions exist:
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Case Dimensions: Although the bullet diameters are nearly identical, the 7.62x51 NATO case is slightly longer and larger in diameter than the .308 Winchester case. This difference might seem minor, but it's significant.
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Chamber Pressure: 7.62x51 NATO operates at higher chamber pressures than .308 Winchester. Firing a 7.62x51 round in a .308 Winchester chamber could result in catastrophic chamber pressure, leading to a dangerous situation.
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Headspace: Headspace is the distance between the bolt face and the cartridge case head. A mismatch here is critical. A .308 Winchester chamber will not reliably hold a 7.62x51 round, potentially causing it to move backward in the chamber and fail to fire, or worse, cause a catastrophic failure.
Why attempting to fire 7.62x51 in a .308 is dangerous:
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Chamber Rupture: The higher pressure of the 7.62x51 NATO round can exceed the .308 Winchester chamber's pressure rating, causing it to rupture. This can result in serious injury or death to the shooter and those nearby. The rifle itself will likely be destroyed.
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Bullet Obstruction: The slightly larger case of the 7.62x51 can cause obstructions in a .308 chamber, leading to a dangerous malfunction or jam. This can result in the rifle being unusable and require significant repair or replacement.
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Improper Ignition: Even if the round manages to fire, the improper fit could lead to inconsistent ignition or incomplete burning of the propellant, producing inconsistent velocities and dangerous pressure spikes.
Case Studies and Warnings
There are no safe case studies to illustrate the outcome of firing 7.62x51 in a .308 chamber. The potential for catastrophic failure is well-documented, and responsible firearm owners would never attempt this. Numerous online forums and gun safety communities warn against such practices. Never attempt to use a 7.62x51 round in a rifle chambered for .308 Winchester.
Identifying Your Cartridge: A Crucial Step
It's crucial to correctly identify your firearm's chambering before loading any ammunition. The markings on the barrel and receiver should clearly indicate whether it's a .308 Winchester or 7.62x51 NATO. If you are unsure, consult a qualified gunsmith or refer to your firearm's manual.
Conclusion: Safety First
The subtle differences between .308 Winchester and 7.62x51 NATO cartridges are significant enough to make attempting to use them interchangeably extremely dangerous. Always prioritize safety by using only the correct ammunition for your firearm. A moment of carelessness can lead to tragic consequences. Never compromise on firearm safety. The risk far outweighs any potential benefit.