7.62 nato is actually speced to a lower pressure than .308 win, it kinda goes the other way in that one, not firing commercial .308 in weak guns like the .308 enfield and such.
however the specs are missleading as he way the military does it is differant the rounds are closer than one thinks. there is a really good discussion in the 308 conversion thread in calibur conversions. at first claance there is a bout 10,000 PSI differance but I belive that is missleading. either way one should be carefull shooting 308 in a 7.62 rifle.
some were I have a really good link on the differances