I think the title of the thread is fine the way it is. To soley blame the shooter is, IMHO, pulling a major ostritch maneuver.
Brobee,
I've been shooting for MANY MANY years, mostly milsurps. I have NEVER seen a K-B using milspec ammo. NEVER. I have seen SIX with reloads.
Ask an IPSC shooter how many KB's they've seen. I'll bet the farm he'll tell you they were all reloads too.
Ever heard of Occham's Razor? Here's a summary:
The simpler the explanation, the better." or "Do not make more hypotheses than necessary to explain something."
Or in even more laymen's terms, when at the Calgary stampede, if you hear hoofprints, think horses - not zebras.
I also note, we have not seen ANY pictures of this blowup despite initial claims of a digital camera. I wonder why? Perhaps it never happened? Or perhaps the pics show a bolt body firing pin channel chalk full of cosmolene goo?
I await the appropriate response from the shooter before speculating beyond "shooter/reloader error".