What's the Difference Between .308 Win and 7.62x51?

There's a lot of confusion regarding the similarities and differences between commercial cartridges and NATO cartridges. The two pairs of rifle cartridges most frequently discussed are .308 Winchester and 7.62x51mm NATO cartridges (and .223 Remington / 5.56x45mm NATO ammo). This guide will help explain the differences between these commercial cartridges and their NATO military cartridge counterparts, as well as which one shooters should use in their rifles.

Are .308 and 7.62 NATO Interchangeable?

If your rifle is chambered in .308 Winchester, you can fire .308 Winchester and 7.62x51mm NATO ammunition in the rifle. If your rifle is chambered in 7.62x51mm NATO, you can only fire 7.62x51mm NATO in your rifle. However, if your rifle is chambered in .308 Winchester, it is recommended to avoid shooting 7.62x51mm NATO on a regular basis. You can check SAAMI (Sporting Arms and Ammunition Manufacturers' Institue, Inc.) for their list of Generally Accepted Firearms and Ammunition Interchangeability.

What's the Difference Between 308 Winchester and 7.62x51mm?

The .308 Winchester and 7.62x51mm NATO are both firing a .308-caliber bullet from very similar cartridge cases. 308 Win ammo has a slightly higher pressure when compared to the 7.62x51 mm NATO, but 7.62x51mm NATO has a slightly thicker case (thicker walls/thicker brass) and slightly longer headspace than 308 Winchester brass. Like .223 Remington and 5.56x45mm NATO, the differences between the .308 Winchester and 7.62x51 NATO make it so the cartridges have limitations when being fired in certain rifle chambers.

Since the .308 Win round has a higher pressure, it is recommended that it not be fired in a rifle with a 7.62x51mm NATO chamber. On the other hand, .308 Winchester-chambered rifles are constructed to withstand a higher pressure, so they can fire 7.62x51mm ammo even though it has a slightly longer chamber and headspace. However, even though the .308 Winchester chambered rifles can shoot 7.62x51mm NATO, it is not recommended to do this frequently.

Recap: .308 Winchester vs 7.62 NATO Ammo

Even though the commercial .308 Winchester cartridges are very similar to their 7.62mm NATO counterparts, their slight differences shouldn't be ignored when choosing which ammo is suited to fire in your rifle.

Looking for Ammo? Check out our selection of 308 Winchester & 7.62 NATO ammo!