The only Achilles heel I see with the Post-64 is the extractor in the right bolt lug. I've seen photos of those blown out with an overload.
Once that happens, one has to put a Sako/M-16 type extractor above the lug. I'm sure that changes the ejection angle, but seems to work.
That's one place where the "three rings of steel" are superior.
DF
