7.62x51 and .308?' is this from the folks at Bulk Ammo
Update: received this from this gentleman:
A few years back a government document was revised from "CUP psi" to
just read "psi" and this wrong information has been repeated over and
over again by folks who should know better.
When you measure 7.62x51 or 308 Win by the same method, you get the same pressure standards.
REAL difference is in "port pressure" where milspec ammo has a
requirement to meet, but commercial 308 Win does not. This is really
only an issue with oprods for M1As and converted Garands.