Just found this , I have been looking for this for some time , it shows in this take from a cartridge guide I use ...the difference between the 2 rounds !!!!
It goes into detail about every thing all the members on this forum have been repeating over and over !!!
For those who need proof !! here it is !!!
I got this from Accurateshooter .com
http://www.6mmbr.com/308Win.html
.308 Win vs. 7.62x51--The Straight Scoop
Before we go much
further, we want to address the oft-posed question "Are the .308
Winchester and 7.62x51 NATO one and the same?" The simple answer is no.
There are differences in chamber specs and maximum pressures. The
SAMMI/CIP maximum pressure for the .308 Win cartridge is 62,000 psi,
while the 7.62x51 max is 50,000 psi. Also, the headspace is slightly
different. The .308 Win "Go Gauge" is 1.630" vs. 1.635" for the 7.62x51.
The .308's "No-Go" dimension is 1.634" vs. 1.6405" for a 7.62x51 "No
Go" gauge. That said, it is normally fine to shoot quality 7.62x51 NATO
ammo in a gun chambered for the .308 Winchester (though not all NATO
ammo is identical). Clint McKee of Fulton Armory notes: "[N]obody makes
7.62mm (NATO) ammo that isn't to the .308 'headspace' dimension spec. So
7.62mm ammo fits nicely into .308 chambers, as a rule." You CAN
encounter problems going the other way, however. A commercial .308 Win
round can exceed the max rated pressure for the 7.62x51. So, you should
avoid putting full-power .308 Win rounds into military surplus rifles
that have been designed for 50,000 psi max. For more information on this
interesting topic, read the following articles: http://www.thegunzone.com/30cal.html" rel="nofollow - Gun Zone's 30 Caliber FAQ ; http://www.cruffler.com/trivia-June01.html" rel="nofollow - Cruffler.com Technical Trivia, June 2001 ; and last, but not least, Steve Redgwell's http://www.303british.com/id36.html" rel="nofollow - .308 vs 7.62x51 Analysis ,
which really provides a definitive explanation. Reloaders should also
note that military ammo often is made with a thicker web. Consequently
the case capacity of 7.62x51 brass is usually less than that of
commercial .308 brass. You may need to reduce recommended .308
Winchester loads by as much as 2 full grains, if you reload with
military 7.62x51 brass, such as Lake City or IMI.
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"White Rhino"
"Everybody's got to believe in something. I believe I'll have another beer." --W. C. Fields
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