The design is so simple and forgiving a design that even the WASR does what it was designed to do--go "pop" when the trigger is pulled with another round chambered after extraction and ejection.
There was a reported incident (according to Col. David Hackworth) where an AK-47 was recovered from a bulldozed site in VN during a fire base construction. It was found buried alongside a VC corpse. "One story, plucked by Kahaner from the Vietnam memoir of Colonel David Hackworth, illustrates the issues. Hackworth came across an accidentally exposed Viet Cong gravesite, yanked out a mud-caked AK, pulled back the bolt, and fired off thirty rounds as if the gun had just been cleaned. "This was the kind of weapon our solders needed and deserved, not the M-16 that had to be hospital cleaned or it would jam," wrote Hackworth."
The Gun, by CJ Chivers, is a good read about the history of the AK-47. If I recall correctly, he writes that it is even made in street bazaars by gunsmiths in Pakistan. Yes, the milled receivers are nice to have if and when you can find one, but they are no more reliable than one punched or stamped out of steel. Imprecise and loose tolerances of parts and design are what contribute to its reliability and not machined, milled or hand-fitted parts. The AK-47 is the Remington 870 pump of military long guns.
