If that case wasn't extracted it wasn't because it didn't have sufficient force being imparted by the gas system,or it wouldn't look like the extractor tried it's ass off to rip the rim off the case.Lacquer coating (which Wolf no longer uses) wouldn't have caused this either.Rumors about it's gluing cases to chambers circulated around the internet but they are untrue.Steel cases are not as elastic as brass,therefore do not conform to the chamber walls as well when fired.Because of this there is some blow-by which causes fouling buildup in the chamber which,added to the fact that Wolf is not very clean burning ammo can cause cartridges with not as much body taper(5.56x45) vs cartridges with more body taper(7.62x39) to not extract as well after firing enough rounds to get that buildup.This is especially true if you start firing brass cased ammo behind steel cased ammo,because now you have an already powder fouled chamber,coupled with a tighter expanding case.The reason lubrication helps this is because it helps keep the residue soft,basically the same reason gas impinged AR's need lubrication to keep them running when really dirty,too much fouling causes sticky extraction because chamber tolerances are tightened.Personally I think for maximum reliability all military small arms should use a fluted chamber to help eliminate this.The Russians just use looser tolerances,but at the expense of some accuracy.