Heat treat is the heart of the knife, I've tested a bone collector 15015 (d2) and it fell right in line with benchmades specs. They say they run their d2 @60-62rc, and my bone collector was 61.25rc. I think they spec it right, saying 60 will be the lowest they want and 62 being the highest. Anywhere in between is good. They outsource their heat treating, so I figure they tell them to shoot in between the two numbers.