Not really a discussion, but more of an FYI/entertainment.

Here is a video of a Russian AK-74 burn-down performed by a Kalashnikov factory. In a nutshell:
- military AK-74M (5.45x39) year of manufacture 2014
- ammo - military 7n6, ammo can seems to be marked year 1977
- at around 480 rounds barrel was drooping, rate of fire varies widely, significant fireballs from the muzzle, bolt carrier sticking in the action.
- at around 580 rounds barrel fails and has a live round stuck in the chamber (probably due to heat melting a cartridge lacquer)
- after the test the receiver and bolt look fine, everything else including the barrel, carrier (bent piston), and muzzle device are unusable.

Interesting points:
- barrel burst around a front handguard mounting point, not at the gas block
- didn't notice any cook offs, although I was expecting to see some after 200-250 rounds
- video was not filmed from the same vantage point so it's difficult to judge when the barrel started drooping, but by 450-480 rounds it was noticeable

I'd like to see them do a burn-down of PKM. I suspect it will probably do 800-1100 rounds until a catastrophic failure.