Why not !!!!
Of course 7.62x39 is not intended for military sniping ....but it could be a great police sniper
About 7.62x39 accuracy.... you must reload ( the 7.62x39 ammo that you can find is for hunting/recreational shooting or military surplus .........for sniping role you need first class components (brass, bullets, powder, pistons ).
About the guns....the saiga/ak is for close combat....is a really rugged design but there are a lot of more accurate guns...(izhmash,Cz, sako and now Remington makes bolt actions in 7.62x39)
.