Original owner?? If not, maybe a prior owner weakened it and started it on it's way to the blow up by using some overloaded handloads before selling it?
I know of one individual that bought a used M27 and had the thing let loose with off the shelf Federal 240 gr JHP, and although he could not prove it, my gunsmith suspected that may have been the case, as the owner experiencing the blow up was a well known customer that did not reload and only used off the shelf stuff.
"Factory" has become such a generic term these days... take the big 305 grain .44 Magnum ammo from Buffalo Bore as an example, it is loaded up to maximum SAAMI specifications and is more intended for use in a Ruger or T/C Contender than S&W's. Someone using that stuff and suffering a blow up could say that they were only using "factory" ammo.
At any rate, I sure pray nothing like that ever happens to me... for whatever reason.