The "not so accurate" reputation 7.62x39 has isnt anything to do with the caliber. Its the guns and ammo we all read about it being used in. AK's and SKS's were never intended to be what we call "accurate". Fit and finish numbers are left WAY open on those guns to allow them to shoot reliably dirty. Many say they have "loose tolerances", this typically isnt the case at all (depending on manufacture of course). Those guns were
designed to have loose fitting parts though. Not a tolerance issue. But NOT beneficial to accuracy!

Its a necesary trade off.
Then the caliber gets a bad reputation because everybody in this country thats shot it including magazine reviewers are shooting surplus ammo or the cheapest crap they can get a thousand rounds of.
The caliber is fine, if applied to a quality rifle with quality ammo there is little it wont do. Iraqis issue it to designated "sharpshooters" in long barrel, high tolerance rifles.
HECK no I wouldnt want it as a sniper... But for most anything else I can think of, YOU BET!
My friend tricked out a high dollar rifle in Ruger .204, and when they were the hot new thing a .17 rim fire. Both
amazing putting holes in paper!!! He was pretty red faced when I watched him shoot a crow square in the chest and it flew away one day. I remind him of it frequently just for fun
Nothing man made is perfect. You try to match up ammo and rifle to the application, but it's all a comprimise at some point.