Can a .308 Fire 7.62x51? Understanding Cartridge Compatibility
The short answer is: yes, but with important caveats. The .308 Winchester and 7.62x51mm NATO cartridges are very similar, leading to frequent confusion about their interchangeability. While they share the same projectile diameter (.308 inch), subtle differences in case dimensions can lead to issues if you're not careful.
The Subtle Differences That Matter
While seemingly interchangeable, the .308 Winchester and 7.62x51mm NATO cartridges have distinct specifications:
- Case dimensions: The 7.62x51mm NATO case is slightly longer and larger in diameter than the .308 Winchester case. This difference is small, but significant.
- Chamber pressure: 7.62x51mm NATO cartridges generally operate at higher chamber pressures than .308 Winchester rounds.
Firing 7.62x51 in a .308 Chamber: The Risks
Firing 7.62x51mm NATO ammunition in a firearm chambered for .308 Winchester can be dangerous. Here's why:
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Overpressure: The larger NATO case could lead to higher pressure within the .308 chamber than it's designed to handle. This could result in:
- Chamber bulges or ruptures: Permanent damage to the firearm, rendering it unsafe.
- Case head separations: A catastrophic failure where the base of the cartridge separates, potentially causing serious injury to the shooter.
- Barrel damage: Increased pressure can stress and damage the barrel, impacting accuracy and potentially leading to failure.
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Inconsistent Performance: Even if the round fires without catastrophic failure, the higher pressure could lead to inconsistent accuracy and potentially damage the firearm over time.
Firing .308 in a 7.62x51 Chamber: A Safer Option
Conversely, firing .308 Winchester ammunition in a 7.62x51mm NATO chamber is generally considered safer, although still not recommended without careful consideration. The larger chamber will accommodate the slightly smaller .308 case. However, the looser fit might lead to a slight decrease in accuracy due to gas leakage.
The Bottom Line: Exercise Caution
While some sources suggest interchangeability, it's strongly advised to only fire ammunition specifically designed for your firearm's chamber. Using the wrong ammunition type can lead to serious consequences, including injury or death. Always refer to your firearm's owner's manual for specific ammunition recommendations.
Beyond the Basics: Understanding Cartridge Markings
Always double-check the markings on your ammunition to ensure it matches the specifications for your firearm. This careful attention to detail is crucial for safe and reliable operation. Confusion between these cartridges is a common cause of accidents; prioritizing safety should always come first.
