The QLA can absolutely be a real problem child and its removal along with proper re-crowning of the barrel have helped in almost every case - usually the improvement is dramatic. I like TC rifles but the QLA is just a very bad idea, IMHO. If you need a false muzzle, then design a rifle with a proper one... one that is removed before firing. QLA generally means quick loss of accuracy to me, but my preference has always been conicals. Maybe the new Pro Hunters will have less a problem if the barrel and QLA tolerances are narrowed.