From what ive gathered whoever installed that barrel for him did it wrong, not torqued properly and created stress point on the receiver walls.
This has not been proven what so ever, SEI despite its sometimes unsavory customer service and other such issues with forums and members which I will Not get into detail now, has government contracts to build and maintain M14 and have been in business for decades, I would suspect they know a thing or 2 about how to install a barrel.
That being said, I am in NO way defending SEIs work or company seeing as how the owner Ron has offered to look at the receiver as well, I would NOT jump to any conclusions right now until experts at springfield have had a chance to look it over. Now as far as I understand the owner of the rifle will not be getting the receiver back so chances are SEI will never get to examine the receiver any ways. I would not jump to conclusions at this time until all the facts are known, I would not try to point a finger at anyone especially if they have offered to help.
The only reason I posted this up was not to bash any one company, I love my Norc, and I love springfields, thats me that my choice. I posted this up simply because I have never seen a break like this before, posted here or on m14forums this is a good chance for all to see what happen and learn from it, either by learning to inspect your rifle more carefully learning what to look for ect.
Points of view and speculations are very important to us all, and to each their own, freedom of speech is very important. That being said I choose not to say anyone is wrong or right with out knowing the ALL the facts.
There are many good theories out there from bad bolt, bad ammo, bad receiver, improper torque of stock, scope mounts, barrels, lets wait till all the evidence is in before we start attacking. And no offence is meant towards deagle2008.