Well guys, still nowhere near any answers or resolution, but some movement on my situation today.
H&K: I emailed them last night, I already had reply in my mail box. Not surprisingly, they say that it was ammo failure. I replied asking because of excessive charge, or case failure? Their reply, and I am going to quote them: "It is very possible."
wut? They also mention that once we get the pistol there, they'll be able to tell more, but I am given no information on how this is supposed to happen.
wut?
Don't get me wrong, I'm very pleased with how quick they are replying my messages, but other than going "it was the ammo", sadly, expectedly, I am receiving no assistance from them. I'm not upset, because personally, I still feel that it was the ammo.
Ammunition Maker: They are stepping up, setting up a call tag to ship the ammunition back to them. They asked if I could get the shell in question loose from the chamber(answer below in "gunsmith"). They are deciding if they should call tag the whole slide also.
Gunsmith(s): They came up with few theories, but in the end, nobody there could say for sure. What really would have helped was if they had another .45 USP to compare mine to, but unfortunately they did not.
I was hoping for "oh, yeah, that's definitely ammo", but they really couldn't say what happened, or how it happened without having undamged USP to compare it with. One guy did try to loosen the chamber/barrel, also the casing stuck inside, but he says that it's like they are welded together.
-End Update-
Next person to say stopping power is getting pistol whipped.
I. CAN'T!!!!!
I can maybe throw the pieces at them.