I doubt that headspace would cause a catastrophic boom with A PROPERLY DESIGNED FIREARM. That is kind of the point. I've seen cases that completely separated in bolt actions that the shooter didn't even know had separated until he pulled out half a case.
So, if there was no evidence put forth that the shooter had packed a case full of pistol powder, I suspect that IT IS something wrong with the design or metallurgy of the firearm.
It happens to all makers. Remember Sako had that run a few years ago of bad steel where barrels were banana peeling.
Getting into this very late, and just commenting on the technical aspects. If a rifle goes kB! that most certainly can be from headspaces (as well as many other issues). It should also be noted that just because headspace is excessive, doesn't mean it's automatically going to blow up.
