I have some boxes of Winchester 7.62x39. I do have problems with the brass casings in my SKS. When the casing would get ejected, it would take out a gouge from either the rim, or half way up the casing. One of those small brass chunks got lodged in my trigger assembly, and my gun started double firing. Rapid firing is not allowed at the range I go, so after the second double fire in a row, I had to stop and pull it apart to see what was going on.
I have 7 boxes left, and I'm not going to to use it in my SKS. I'm going to stick to Wolf Steel Cases.
From what I've been told, the American made 7.62 is ever so slightly differetn and is made for an american made gun, like the Ruger Mini 30. And the Russian stuff is for the russian guns.