It used to be made in Russia, but TulAmmo is now making it under their own brand at the Tula plant in Russia.
I've actually not had much issue with Wolf through the years, even when it was made by Tula, except for the occasional hard primer.
(Tula is another story)
People can have issues with steel cased ammo if you switch back and forth from brass and to steel without cleaning.
Also, steel cases are inherently less reliable since they expand differently than brass.
I wouldn't recommend it for serious use in most guns, because of the fact that it is inherently less reliable (with the exception of AK-47's, but you should test it out first).
7.62x39 has a pretty extreme taper on the case and this makes the round inherently more reliable...