The question of whether a .308 Winchester (7.62 NATO) rifle can shoot 7.62x51mm ammunition often arises, leading to confusion. The short answer is: generally, yes, but with important caveats. While the calibers are very similar, there are crucial differences that need careful consideration.
The Similarities and Differences Between .308 Winchester and 7.62x51mm NATO
Both .308 Winchester and 7.62x51mm NATO are centerfire rifle cartridges with nearly identical bullet diameters. However, the subtle variations in case dimensions and chamber specifications are significant.
- Bullet Diameter: Both cartridges have virtually the same bullet diameter, around 7.82mm. This is why the confusion exists.
- Case Dimensions: While the bullet diameter is nearly identical, the case dimensions—specifically the shoulder angle and case length—differ slightly. This is the key difference. The 7.62x51mm NATO cartridge is slightly longer and has a sharper shoulder angle.
- Chamber Specifications: This is where the potential for problems arises. A .308 Winchester chamber is designed to handle the specific dimensions of the .308 Winchester cartridge. While a .308 Winchester rifle might chamber a 7.62x51mm round, the slightly larger dimensions of the 7.62x51mm case could lead to problems.
The Risks of Firing 7.62x51mm in a .308 Winchester Chamber
Firing 7.62x51mm ammunition in a .308 Winchester chamber can result in several dangerous scenarios:
- Increased Chamber Pressure: The slightly larger case of the 7.62x51mm round could create excessively high chamber pressure when fired in a .308 Winchester chamber. This can lead to damage to the rifle, including:
- Case Head Separation: The cartridge case could rupture near the base, causing potentially serious injury.
- Barrel Bulging or Burst: The pressure could cause the barrel to bulge or even burst, rendering the weapon unusable and potentially causing injury.
- Bolt Damage: Excessive pressure could damage the bolt and related mechanisms.
- Accuracy Issues: Even if the round fires without catastrophic failure, the slightly different case dimensions could lead to inconsistent accuracy and potentially dangerous variations in bullet trajectory.
The Safe Approach: Understanding Your Rifle's Chambering
The safest practice is to always only fire ammunition specifically designated for your rifle's chambering. Check your rifle's markings clearly—they'll specify the caliber it's designed for. Never assume compatibility based on the close similarity of caliber names. If you're unsure, consult a qualified gunsmith or firearms expert.
Conclusion: Prioritize Safety
While the .308 Winchester and 7.62x51mm NATO cartridges are very similar, the risks of mixing them are too significant to ignore. Prioritizing safety and following the manufacturer's recommendations for ammunition is paramount. The potential for catastrophic weapon damage and personal injury outweighs any perceived convenience of using potentially incompatible ammunition. Always double-check your ammunition before loading and firing any firearm.
