The Beginning Of the 308 Winchester It is commonly misunderstood that the 7.62x51mm is interchangeable with the .308 Winchester. This is not true, as the modern .308 Winchester cartridge generates higher pressures than seen in the military 7.62x51mm. Indeed, the NATO round was developed based on the 308 Win. Therefore, https://reloadprimer.com/product/1000-rounds-of-223-ammo-by-winchester-usa-55gr-fmj-2/