Can You Shoot .308 Out of a 7.62x51mm? Understanding Cartridge Compatibility
The short answer is: Generally, yes, but with crucial caveats. The question of shooting .308 Winchester (often referred to as .308 Win) ammunition from a 7.62x51mm NATO rifle hinges on a subtle but significant difference in cartridge dimensions. While both cartridges use a nearly identical .308 inch diameter bullet, there are variations in case dimensions that can impact firearm safety and function.
The Subtle Differences That Matter
While often used interchangeably, .308 Winchester and 7.62x51mm NATO are not precisely the same. The key difference lies in the cartridge case:
-
Case Dimensions: The 7.62x51mm NATO cartridge case is slightly larger in several dimensions than the .308 Winchester case. This seemingly minor difference can lead to problems if .308 Win ammunition is fired from a rifle chambered specifically for 7.62x51mm NATO.
-
Chamber Tolerance: 7.62x51mm NATO chambers are designed with a slightly larger tolerance to accommodate variations in military-grade ammunition. This is crucial for reliability in harsh conditions. .308 Winchester ammunition, produced to tighter commercial tolerances, can experience higher chamber pressure in a 7.62x51mm NATO chamber.
The Risks of Mismatched Ammunition
Firing .308 Winchester ammunition in a 7.62x51mm NATO chamber might not always cause immediate failure. However, it introduces several risks:
-
Increased Pressure: The slightly larger NATO chamber allows for more expansion of the .308 Win case during firing, resulting in higher chamber pressure. This elevated pressure can lead to:
- Bulging or rupturing of the case: This can cause serious injury or damage to the firearm.
- Damage to the firearm's action: The increased pressure can stress and damage internal components.
- Increased risk of malfunction: Higher pressure can interfere with reliable cycling and extraction.
-
Accuracy Issues: The loose fit between the .308 Win case and the 7.62x51mm NATO chamber can affect accuracy.
When It's (Generally) Safe
Many modern firearms designed for 7.62x51mm NATO are capable of handling .308 Winchester ammunition without significant problems. However, manufacturers usually specify which cartridges are suitable for their specific weapons. Always consult your firearm's owner's manual before using any ammunition other than that explicitly recommended by the manufacturer.
The Safer Approach: Stick to the Manufacturer's Recommendations
The safest and most reliable practice is to use the ammunition specified by the firearm manufacturer. Using the correct ammunition is essential for the safety of the shooter and the longevity of the firearm. While some rifles can handle both, the potential risks of using mismatched ammunition outweigh the convenience. Choose the correct ammunition for your specific rifle to avoid potential hazards.
Disclaimer: This information is for educational purposes only. Always consult a qualified firearms expert and adhere to all safety regulations when handling firearms and ammunition. Improper use of firearms can result in serious injury or death.
