Lever arms used to have some, but I think All the Norinco stuff has all but dried up.
I can attest to that MFS stuff being corrosive, I had some nice bright orange blooms of rust on my gas piston after it just sitting a week before cleaning it. And I had it cleaned before i shot it, used some little norinco ammo and no rust.
My friend hasn't cleaned his SKS since 2001 and no rust with norinco ammo.
On another board, there was talk of soon a big Shipment and continuing supply of Norinco ammo coming into the country, but I'll believe it when I see it.