feed ramp/chamber at the 6 oclock position
somebody was bringing up quantum physics or something and how it cannot possibly relate to overpressure in the chamber of a glock resulting in a KaBoom, but that is actually not really the thing to be looking at here.
the oversize chamber at the 6 o clock position allows the brass to bulge a bit, resulting in many possible failures. one can be that once the brass has bulged it can hang in the chamber and does not allow the slide to cycle which builds pressure in the barrel. and then i guess we all know what happens next. or do we need to take a college course to tell us that if the brass can't exit the chamber, and if the bullet can't exit the barrel, then all the stuff in the middle has to go somewhere. remember that autopistols depend on blowback to function.
yes, reloaded brass can be weaker, making this possibility more probable. rarely, factory ammo can have poor brass. however you look at it, it is POSSIBLE, however unlikely.
now with all that said, i sure hope to god nobody has to suffer any kind of injury from indulging in such a wonderful sport as handgunning and reloading. good luck to all you guys who reload. i used to do it myself. i hope you don't get hurt.