There's an infographic going around talking about the interchange between .308 Winchester and 7.62x51mm NATO.
The max pressure for 7.62x51mm NATO is not 50,000 psi, it is 50,000 CUP. 50,000 CUP, in this case, is equivalent to 60,000 psi.
Next, every weapon designed for NATO that fires 7.62x51mm NATO gets proofed with a 140% pressure charge. That's 84,000 psi and the gun must not break to be accepted. That's a pretty sizable safety margin.
The 62,000 psi max pressure for SAAMI is intended to the the absolute limit with a 52,000 psi maximum average pressure.
The differences in headspace has resulted in ruptured cases in some rare instances when .308 is fired in a NATO spec chamber.
Another important difference between .308 and NATO is the leade. Mil guns tend to have longer leades and that tends to lower the actual chamber pressure in the gun. This is for reliability when the gun gets really hot.
I guess the good news is with the ban on importing parts kits with intact barrels, most "7.62x51mm" battle rifles you'll encounter are actually going to have .308 chamber dimensions.
Anecdotally, when was the last time you heard of someones battle rifle blowing up where it wasn't sketchy surplus ammo (which should nominally have been NATO spec to begin with) or a gross error on the reloading bench?
If this was actually a real problem there'd be a lot more broken gun stories out there on the internet because every negative thing in the world gets a thread.
The max pressure for 7.62x51mm NATO is not 50,000 psi, it is 50,000 CUP. 50,000 CUP, in this case, is equivalent to 60,000 psi.
Next, every weapon designed for NATO that fires 7.62x51mm NATO gets proofed with a 140% pressure charge. That's 84,000 psi and the gun must not break to be accepted. That's a pretty sizable safety margin.
The 62,000 psi max pressure for SAAMI is intended to the the absolute limit with a 52,000 psi maximum average pressure.
The differences in headspace has resulted in ruptured cases in some rare instances when .308 is fired in a NATO spec chamber.
Another important difference between .308 and NATO is the leade. Mil guns tend to have longer leades and that tends to lower the actual chamber pressure in the gun. This is for reliability when the gun gets really hot.
I guess the good news is with the ban on importing parts kits with intact barrels, most "7.62x51mm" battle rifles you'll encounter are actually going to have .308 chamber dimensions.
Anecdotally, when was the last time you heard of someones battle rifle blowing up where it wasn't sketchy surplus ammo (which should nominally have been NATO spec to begin with) or a gross error on the reloading bench?
If this was actually a real problem there'd be a lot more broken gun stories out there on the internet because every negative thing in the world gets a thread.
