David: I'm thankful you were not seriously injured.
As mentioned, right now METL here in Phoenix is finishing a formal failure analysis of a chamber blow out
http://metl.com/services/
The 3 threads on DoubleGun
http://www.doublegunshop.com/forums/...=356377&page=1
http://www.doublegunshop.com/forums/...999#Post354999
http://www.doublegunshop.com/forums/...=357105&page=1
By the appearance of the blow out, I
think there is little doubt that there was an obstruction, likely at the forcing cone, and would suggest that you examine every empty used prior to the event for a missing base wad or piece of plastic. AND please check the shell that was in the chamber for expansion of the head, and an indentation on the head from the extractor. Because of the plastic deformation of the chamber, I am
quite confident that this was not simply a fracture of the barrel wall.
A formal failure analysis costs more than $1000, but if you would like to send me the remains, I could measure the wall thickness around the blow out and also ask the Metallurgical Engineer at METL for his opinion. Possibly a visual exam of the edges would confirm my thoughts.
Also please send the remnants of the shell, or post an image of the head.
Another option would be destructive testing of the remains, with sectioning and photomicrographs. This is the big $s.
BTW: I'll add your images here, with an attribution
http://www.picturetrail.com/sfx/album/view/24513874
Feel free to contact me at
drewhausemd@yahoo.com if you'd like to discuss further testing.
Drew Hause M.D.