The 7.62x51mm NATO, also known as the .308 Winchester, is a rimless, bottlenecked rifle cartridge developed in the 1950s. It features a thicker brass case than the commercial .308 Winchester cartridge, with a thickness of 0.020 inches, as required by the NATO standard. This thicker case is designed to withstand the higher pressures generated by military firearms and to provide increased durability for use in combat conditions.

The 7.62x51mm NATO cartridge uses a large, heavy bullet with a high sectional density, allowing it to penetrate deeply and deliver a large amount of energy to the target. It is used in a variety of firearms, including the M14 rifle, the FN FAL, the G3 battle rifle, and the M60 machine gun. The cartridge has been used in numerous conflicts around the world, including the Vietnam War, the Gulf War, and the War in Afghanistan, and is highly effective at stopping enemy soldiers, vehicles, and other targets. Despite its recoil and muzzle blast, the 7.62x51mm NATO remains a popular cartridge for military and civilian use due to its accuracy, reliability, and stopping power.