The SKS are built pretty loose to begin with. You could have the barrel and chamber checked, as well as the gas system. Not saying this is what happened-but some times previous owners find it fun to shoot clip-after clip-after clip, getting these so hot they lose a lot of accuracy. The 7.62 x 39 ammo surplus is sometimes loaded kinda so-so. I think Wolf is probably closer to a more consistent "surplus" round. Just My opinion. However a new barrel is pretty cheap. let us know what you find.