Odd Case Head Separation

[WinM70]

Question about case head separation.

Attached is a picture of a .30-06 case with some kind of a case failure in it. I am familiar with case head separation, the ring as the case stretches and thins. But what causes this failure? I have a few (two or three) cases that have failed in this manner, with only two loads. I am shooting 180 gr SPBT with 55.0 gr of IMR 4350, FL sized.

See attached picture.

 

[LONGSHOOTER]

I call that a pressure excursion. I see it on occasion in full house shotgun trap loads where the case isn't up to the task.

 

[LoneTraveler]

I have only seen a few splits similar to the one in the picture. They showed up on some Military Brass of an unknown age. I was loading cast gas check bullets, using Lyman data. A couple split the funny T shape near the base of the case and run up the side nearly up to the shoulder. The brass had just got old and hard. I pulled the bullet salvaged the powder and mashed the brass for recycle. If the cases are new I would contact the Brass Manufacture about this problem. If the brass is old, Retire it. This kind of blow out could cause hot gas cuts in the chamber. Good Luck

 

[MagnumManiac]

That is a fault in the brass case from forming/drawing, it is not caused by resizing or excessive pressure.
I have only seen it myself once, in PMC brass many moons ago.

Cheers.
gun)

 

[Bill Johnson]

That is a fault in the brass case from forming/drawing, it is not caused by resizing or excessive pressure.
I have only seen it myself once, in PMC brass many moons ago.

Cheers.
gun)

Intermediate draw scratch or nonmetallic inclusion probably. Yugo brass had that issue some years ago.