At 600 rds. you’d need a belt fed weapon, a shooter and a feeder. As far as I know there aren’t even any standard AKs that are belt fed. That, of course, doesn’t rule out the Russians using the basic AK mechanism for a crew served weapon.
“...using the basic AK mechanism for a crew served weapon.”
Fire 600 rounds and while you are changing magazines, you could also take time to change your melted barrel.
However,if you want a long barrel, bipod-mounted, magazine-fed LMG with an AK-47-pattern mechanism, you are talking about the RPK:
http://en.wikipedia.org/wiki/RPK
If you want a long barrel, bipod-mounted, belt-fed LMG in 7.62x39mm, you are talking about the RPD: