308 Winchester was a massive success and quickly became one of the most popular cartridges for big game hunting around the globe.308 Win Features 308 Winchester was developed in 1952 as a hunting round for Winchester’s new Model 70 and Model 88 rifles. 308 Win dimensions, firing a commercial round at max pressure in a chamber with a large headspace can be disastrous. While it is possible in some scenarios to fire a commercial round through a 7.62 NATO chamber cut closer to. Thicker military brass can stretch further and fill the extra space found in a military chamber. In a larger chamber, the thin walled brass can actually burst. 308 Winchester brass can stretch by 0.008″ or more during discharge. Overall, there can be up to a 0.013″ difference between the two with military chambers measuring longer than commercial.Ĭommercial. Winchester headspace is around 1.630″ while the 7.62mm NATO’s headspace is closer to 1.6405″. While the exterior dimensions of both cartridges are the same, the dimensions of their chambers are not. 308 Win chamber, but the reverse is inadvisable.įull-auto weapons tend to prefer thicker brass, and the 7.62mm NATO is built to stretch in a wide range of chambers. Therefore, general consensus dictates it’s perfectly safe to fire 7.62 NATO in a. As a result, commercial rounds can be up to 12,000 psi hotter than NATO. With the same exterior dimensions, this means there’s more room for powder in the. Generally 7.62mm NATO brass is thicker than its commercial counter part. The Bureau of Alcohol, Tobacco, Firearms and Explosives advises all shooters to check the barrel stamp of their firearm and only firing the rounds advised by the weapon’s manufacturer. 308 Winchester rounds are rated for a slightly higher pressure than 7.62x51mm NATO. 308 Winchester and 7.62x51mm NATO cartridges.308 vs 7.62, Notable Differences PressureĪccording to the Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI), it is not considered “unsafe” to fire either round in weapons chambered for either. 30 caliber rounds referred to as “.308” or “7.62,” this article will focus specifically on the. 308 vs 7.62 NATO: These two common cartridges may seem the same, but they’re not identical.