Originally Posted by glocknut
Oh... So some of the military surpluss rifles that have 762 nato marked on them are not suited for regular 308 ammo like the soft points and such?
That's correct gn. The exterior case dimensions are identical, but the .308 max pressure is 65,000 as opposed to 55,000 for the 7.62x51. A max load .308 fired through a rifle marked as 7.62x51 will be hotter than what the rifle was designed for and will eventually beat the gun loose.
A good example of this would be all those reworked Mexican/Spanish Mausers in 7.62x51. These are old rifles and 65000 would be hot enough to either beat the snot out of the gun or worse yet, grenade it. Same thing goes for older semis (like the CETME) too...the hot .308 loads will eventually damage the gun.
7.62 in a .308 = okay
.308 in a 7.62 = not okay