True M14's may be chambered this way but not springfield rifles with national or super barrels, have seen three recently with headspaces of 1.632, 1.632, AND 1.6315 this last one is almost min 308 SAAMI, and the minimum 7.62 NATO exceeds max of 308, have heard of no problem shooting either from a number of people, but have read in M14 SHOP MANUAL (Jerry Khunhausen) that there is a difference and for liability reasons to stamp barrel EITHER 308 win or 7.62NATO (This liability issue is for gunsmiths building gas guns.) I have posted this topic before because of my concern of using significant amount of LC brass I own, compliments of the Corps.
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The beauty of the second Amendment is that it is not needed until they try to take it. T JEFFERSON