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 distinct calibers, and the answer isn't a simple yes or no. Let's delve into the specifics.
The Key Difference: .308 Winchester vs. 7.62x51mm NATO
The crucial point is that .308 Winchester and 7.62x51mm NATO are not identical, despite their near-identical projectile diameters. While functionally similar, they have subtle differences in chamber dimensions, particularly in case length and pressure.
-
Chamber Dimensions: The 7.62x51mm NATO chamber is slightly larger than the .308 Winchester chamber. This difference is critical for safety.
-
Pressure: 7.62x51mm NATO cartridges operate at higher pressures than .308 Winchester cartridges.
Shooting .308 Winchester in a 7.62x51mm NATO Chamber: Generally Safe
Generally, firing .308 Winchester ammunition in an AR-10 chambered for 7.62x51mm NATO is considered safe. The larger chamber accommodates the smaller cartridge, and the lower pressure of the .308 Winchester round poses no immediate danger of over-pressure. However, this practice isn't ideal. The looser fit can lead to decreased accuracy and potentially increased wear on the chamber over time.
Shooting 7.62x51mm NATO in a .308 Winchester Chamber: Extremely Dangerous
Conversely, firing 7.62x51mm NATO ammunition in an AR-10 chambered for .308 Winchester is extremely dangerous and should never be done. The higher pressure of the 7.62x51mm NATO round could cause catastrophic chamber failure, leading to serious injury or death. The rifle could also be irreparably damaged.
Manufacturer Specifications are Paramount
Always check the manufacturer's specifications for your specific AR-10 rifle. The markings on your rifle will clearly indicate the caliber it is chambered for. This information should be consulted before using any ammunition.
Conclusion: It Depends on the Chambering
In summary, whether an AR-10 can shoot both .308 and 7.62 depends entirely on its chambering. An AR-10 chambered in 7.62x51mm NATO can generally fire .308 Winchester rounds (but it's not recommended for long-term use), while an AR-10 chambered in .308 Winchester should never fire 7.62x51mm NATO rounds. Always prioritize safety and follow the manufacturer's instructions. The consequences of ignoring these warnings are severe. Responsible gun ownership includes knowing your firearm's specifications and the ammunition it's designed to handle.
