.308 vs. 7.62x51mm

Apparently the maximum cartridge headspaces are the same, but the chamber headspace is different.  According to one article (apparently by SayUncle, on an early team blog with Eric S. Raymond, Smallest Minority, and others):

Chamber Headspace
	7.62x51mm	.308 Winchester
Go	1.6355"	1.630"
No-Go	-	1.634"
Field	1.6455"	1.638"

Cartridge Headspace
	7.62x51mm	.308 Winchester
Minimum	1.630"	1.627"
Maximum	1.633"	1.633"
Average	1.6315"	1.630"

SAAMI has a .308 Win spec up on their site.  It would seem to indicate that the min/max dimensions for .308 are 1.630"-1.640" chamber and 1.627"-1.634" cartridge, slightly different from the above, although there have been revisions of the standard.  I'm still looking to see if the NATO standards are available.

According to an old rec.guns post by Bartbob: "New cases typically end up with a fired-case headspace dimension of about .001-inch shorter than the chamber's actual headspace."  So if using fired brass to estimate chamber headspace, add 0.001" to the mic'ed dimension.

As an aside, TM 9-1005-223-10 is the M14 operator's manual.