The question of whether an AR-10 can shoot both .308 Winchester and 7.62x51mm NATO often arises due to the common misconception that they are interchangeable. While closely related, they are not identical, leading to potential safety issues if used incorrectly. The short answer is: generally, yes, but with important caveats.
The Subtle Differences Between .308 Winchester and 7.62x51mm NATO
The key to understanding this lies in the subtle differences between the two cartridges:
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.308 Winchester: Developed by Winchester, it's a commercial cartridge. It has slightly less pressure and a slightly smaller case diameter than its military counterpart.
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7.62x51mm NATO: This is the military standard cartridge, designed to withstand higher pressures.
While the bullets are very similar in diameter (both are approximately .308 inches), the crucial differences lie in the case dimensions and maximum chamber pressure. This means a rifle chambered for one might not safely handle the other.
AR-10 Chambering and its Implications
Most AR-10s are specifically chambered for either .308 Winchester or 7.62x51mm NATO. Firing the wrong ammunition in an improperly chambered rifle can lead to catastrophic failure, causing serious injury or death.
Here's a breakdown:
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AR-10 Chambered for .308 Winchester: These rifles are generally not designed to handle the higher pressures of 7.62x51mm NATO ammunition. Using 7.62x51mm in a .308 chamber can result in overpressure, potentially causing a rupture of the chamber, barrel, or receiver.
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AR-10 Chambered for 7.62x51mm NATO: These rifles can generally handle .308 Winchester ammunition. However, it's crucial to check the manufacturer's specifications. While the lower pressure of .308 is less likely to cause failure, some manufacturers explicitly advise against it. Consistent use of .308 Winchester in a 7.62x51mm chamber might lead to increased wear and tear over time.
Identifying Your AR-10's Chambering
Always check the markings on your rifle's receiver or barrel to confirm the chambering. It will explicitly state either ".308 Winchester" or "7.62x51mm NATO."
Safety First: Always Use the Correct Ammunition
This cannot be stressed enough. Using the incorrect ammunition in your AR-10 is incredibly dangerous and should never be attempted. Always double-check your ammunition before loading and firing.
Conclusion: Know Your Cartridge, Know Your Rifle
While many refer to .308 and 7.62x51mm interchangeably, they are not functionally identical. Understanding the specific chambering of your AR-10 is paramount to ensure safe and reliable operation. Always prioritize safety and consult your firearm's manual for the manufacturer's recommendations. Ignoring these guidelines can have serious consequences.
