Blown primer. New rifle. Only 1 round fired.

[Robobiss]

Since we are all spitballing here and OP is definitely going to send it back, I’ll throw in a scenario just for fun.

What are the chances that it is chambered correctly in 280AI like a lot including OP seem to think, but they accidentally chambered a .277 barrel in 280AI instead of a .284? What else would cause crazy pressure like that aside from some seriously effed ammunition?

Anyone?

 

[Jason Snyder]

What else would cause crazy pressure like that aside from some seriously effed ammunition?

Excess headspace.

 

[Robobiss]

Excess headspace.

Come on now, let’s not be too realistic. I really thought I was onto something

 

[Harvey_NW]

Excess headspace.

Can you explain? I understand that excess headspace can cause pressure signs because there's extra space in the chamber and the case head slaps the bolt face typically leaving an ejector mark and/or swipe, but to cause an actual pressure spike to this extent I just don't see how it's possible. If anything I would suspect an under spec chamber, or with that much pressure something like a 277 bore.

 

[SDHNTR]

A cartridge rattling around all sloppy inside an oversized chamber can cause all sorts of problems. Misaligned bore. Dramatically stretched out brass (you can see that ring indicating near case head separation). Primer gas escaping and popped primers as the case head bounces off the bolt face. None of it good.