The question of whether a .308 Winchester can shoot 7.62x51 NATO ammunition is a common one, and the short answer is: generally, yes, but with crucial caveats. The two cartridges are very similar, leading to confusion, but there are important distinctions that affect firearm safety and longevity.
.308 Winchester vs. 7.62x51 NATO: Subtle Differences, Significant Implications
While visually almost identical, the .308 Winchester and 7.62x51 NATO cartridges have subtle differences in their dimensions and pressure levels. These seemingly minor variations can have significant consequences when fired in a firearm chambered for either round.
Key Differences:
- Chamber Dimensions: 7.62x51 NATO chambers are generally slightly larger than those designed for .308 Winchester. This is to accommodate the higher pressures sometimes generated by 7.62x51 ammo.
- Pressure Levels: 7.62x51 NATO ammunition is typically loaded to higher pressure than .308 Winchester ammunition. This is a critical difference.
The Risk of Mismatched Ammunition:
Firing 7.62x51 NATO ammunition in a firearm chambered specifically for .308 Winchester can lead to:
- Overpressure: The higher pressure of the 7.62x51 round could exceed the design limits of the .308 Winchester chamber, potentially causing catastrophic failure of the weapon. This could result in serious injury or death to the shooter and bystanders.
- Damage to the Firearm: Even if the firearm doesn't immediately fail, repeated firing of 7.62x51 ammo in a .308 chamber can cause gradual damage to the action, barrel, and other components, reducing its lifespan and accuracy.
When it Might Work (and Why You Shouldn't Rely On It):
Some .308 Winchester rifles might be able to handle 7.62x51 NATO ammunition without immediate catastrophic failure. This is because some manufacturers build .308 Winchester chambers with slightly larger dimensions, allowing for some degree of overlap. However, this is not guaranteed. The tolerances vary significantly between manufacturers, and relying on this possibility is extremely dangerous.
The Bottom Line: Safety First
The safest and most responsible practice is to only use ammunition specifically designed and marked for the firearm's chambering. The slight differences between .308 Winchester and 7.62x51 NATO cartridges pose a substantial risk of firearm malfunction and serious injury. Never compromise safety for convenience or assumptions. Always check your firearm's owner's manual for explicitly stated ammunition recommendations.
Ignoring these safety precautions could have severe consequences. Always prioritize responsible gun handling and ammunition selection.
