I am pulling this from a pretty dusty corner of my memory, so take it for what it's worth, but I seem to recall that early Mini-30's had .308 bores (just like early U.S.-mfrd 7.62x39 used .308 bullets,) but switched to a .311 bore at some point in its production life. Specific dates elude me, but mid-late '90s rings a rusty bell.
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