A recent thread addressed this issue and I think there is new information regarding the tinifer hardening process. FWIW I just did an amorers course March 16th. I don't claim to know it all but this is what we were taught. Glock has this year begun using a gas nitration method of hardening the slide and barrel. This is being done in Smyrna GA. The tenifer process apparently is too harmful to the enviroment and can't be done in the states. The "new" enviromentally friendlier process is supposed to be harder/more durable than tenifer. Who really knows how it will hold up but apparently we will be the guinea pigs.