Looks like some Kabooms -----> (http://img151.imageshack.us/img151/7631/glockglove.jpg)
I hate blaming ammo when this also happened with a couple of factory rounds. The ammo MIGHT have contributed, but the bigger role IMO is the firearm.
http://www.glocktalk.com/forums/showthread.php?t=1519781&page=2
There has been a few articles on this
And yeah, S&W does point the finger at AMMO in every one
Maybe The Shadow can log on and get one of those Underwood 135's to see what's there? Rapid fire with possibly an upper end round in a striker fire helps open the door.