Lots of folks like to blame their shooting on the gun. Other threads touch on this, somebody who is lacking in natural talent and/or does not shoot much and does not learn much will shoot poorly and it was "that damned gun" or "that cheap factory load". They proceed to buy a better gun and more expensive ammunition in hopes of improving ability. Eventually the excuses make themselves:
"Does that rifle shoot that poorly at 100 yards?"
"Sure does, what a cheapo commie junker, ha ha. Not me at all".
In truth, a good SKS or a new properly built AKM will shoot good enough to hit a man if the shooter does his part out to 400 yards or possibly further if he can use the sights and knows the dope. Even with cheap steel case stuff. A gun that isn't shot out or with a bad barrel or other issue is accurate enough for that. The dope isn't too impressive, in all truth, but it shoots flat enough for a practiced shooter to use practically for combat at those ranges. 200 yards/meters is a gross underestimation. Let us not forget that there are/were plenty of M-16's and M4's with enough rounds through them, loose spec, that would shoot 3.5 MOA eventually and still be judged to be combat effective to 400+ meters.
I'd be more concerned if a skilled marskman, cool under fire and a hardened veteran was taking shots at you at 500 meters with an AKM or SKS, even with irons, then someone who lacks talent AND training with a proper scoped marksman rifle at the same distance. I'd be more afraid of the man than the rifle, and more concerned about a man who can use a less accurate weapon/cartridge than someone who can't utilize a more accurate weapon/cartridge.
Let us not forget line soldiers used to make shots with 45/70 and 455-577 Martini Henrys, ect., at ranges 600+. They didn't always hit their targets, with old fashioned rifled barrels that weren't nearly as good as today's, but with weight of fire they could inflict casualties and make an impact. How many people, the same kind with the big flapping jaws and maws telling OP the 7.62x39 is no good past 200 yards, would tell you a 45/70 can't hit anything past 100 yards because of the dope? Then consider that blackpowder shooters and others can hit targets at long range with cheap home cast bullets.
People have become so obsessed with flat shooting in combat for so many decades people forget that it doesn't neuter a gun to have a rainbow trajectory. Its insane. Is the old spitzer ball better than the old round nose ball? Yep. But if you loaded a 230 grain round nose into a 30-06 or 30-40 Krag, gave it to a decent rifleman, give him some shots to figure out his holdover and sights, you would be a man in severe danger if he wanted to hit you out in the open at 600 yards with a Springfield 03 or Krag.