case separation. Please help

[Ciliman21]

Had a case separate about a 1/2 " from the base after it was fired(191th rd of the day). The upper portion was stuck in the camber. I got it out.

Me a question is what could cause this?

Specs

Daniel defense 10" upper About 500 rds though it (this was the first issue).

Case PNW ARMS 300 BLK. 1rst or 2nd reload
Bullet 150gr sierra spitzer #2130
13.4 accurate #9(#88 lee auto disk. Check powder weight on scale every 10 or so rds)
Cci41 primer
2.116. Col(no reason just where is landed)

Lee dies with factory crimp set up per instruction

Also had slightly flat primers and some cases not all.

All rounds chambered fine and all fit sheridan gauge.

At 50 yrd with a with a vortec sparc it hold very tight groups. (By my standards)



Any thoughts would be greatly appreciated.

[Dr.Phil]

Bad luck on brass is all.
From your description, your loads were all safe.

What was the head stamp on the PNW brass?

[dead-bird]

Brass stretches normally with use and eventually, over time, wears out.

You just found the upper limit on that particular piece of brass.

[batman4706]

I've had a few of those, that's why I do the "paper clip test" on all my cases prior to processing. Since using this procedure I haven't had any separations, I have caught a number of bad cases before sizing.

[remannino]

I've had a few of those, that's why I do the "paper clip test" on all my cases prior to processing. Since using this procedure I haven't had any separations, I have caught a number of bad cases before sizing.

What is the paper clip test?

[mrgein]

Brass stretches normally with use and eventually, over time, wears out.

You just found the upper limit on that particular piece of brass.

Actually with out knowing how many times it had been fired he really didn't find anything.

[mrgein]

I've had a few of those, that's why I do the "paper clip test" on all my cases prior to processing. Since using this procedure I haven't had any separations, I have caught a number of bad cases before sizing.

What is the paper clip test?

+1

[bunnellbob]

Some guy"s use a slightly bent paper clip, or a dental pick, to set down inside the shell to "feel" for grooves. This could tell you possibly in advance you might need to discard that case before something might happen to it.(case seperation) Hope this helps

[Ciliman21]

Bad luck on brass is all.
From your description, your loads were all safe.

What was the head stamp on the PNW brass?

That is the head stamp that I posted.

And I since have checked 300 of my 600 cases with a paper clip they all felt fine.

I'm going to reset my dies and make sure the cases get lubed appropriately.

Thanks for the input

[Ciliman21]

secondary question. 100rnds for the day were 150 hornady boattails, the last 100 was sierra flat base. most of the sierra bullets had flat primers and the hornady didnt not all rounds loaded at the sametime.

so will flat base bullets have higher pressure?