It could have been worse!!!!!

[Bravoman]

Working up loads for my 338 lapua mag nosler brass on its 6th load and last shot of the day got a case head separation. Be careful and mindful of your brass. No signs that I could tell from the out side after perp and loading. I will definitely be checking inside the cases more vigorously with a scope. Didn’t notice the rest till that last one that actually separated in my chamber.

On a side note I think I found my load but I might be working brass to much when I’m resizing to bump shoulder back .001” base of case measures .5785 new .5845 fired and .5810 resized with .001 bump to shoulder .

 

[1KPerDay]

A dental pick would likely feel a groove inside

 

[Bravoman]

A dental pick would likely feel a groove inside

Yup on it now , should have been doing that since the beginning. Live and learn.

 

[Bazoo]

Glad it wasn’t worse! Awesome pictures though.

 

[jmorris]

From the outside they look suspect.



This is the fastest way to quantify wall thickness I have found.



Of course you wouldn't harm the case, like this, just slide it on and off watching the indicator.



Once you can measure the change in thickness, you can correlate that with how much you have to trim and play with your die settings to mitigate both issues.

 

[Bravoman]

From the outside they look suspect.

View attachment 1190799

This is the fastest way to quantify wall thickness I have found.

View attachment 1190798

Of course you wouldn't harm the case, like this, just slide it on and off watching the indicator.

View attachment 1190797

Once you can measure the change in thickness, you can correlate that with how much you have to trim and play with your die settings to mitigate both issues.

These are all of the ones I shot that day. The ones you marked up top is just the expansion os the case in the chamber of you look at the bottom roll they have the same ring about an 1/8” of an inch down.

 

[Chuck R.]

These are all of the ones I shot that day. The ones you marked up top is just the expansion os the case in the chamber of you look at the bottom roll they have the same ring about an 1/8” of an inch down.

I suspect that using a dental pic or a paper clip will show that at least those in the lower picture (that jmorris marked) are about to also have separations. The times I have had a case head separation, there were more pieces in that "lot" that were also on there way out, provided they all received the same consistent prep and sizing during their lifespan.

 

[jmorris]

Sometimes it is not even that obvious. Even if you won't feel it with a pick, its thinner.

 

[jmorris]

You might not be able to detect a few thousandths unless you cut it open but the indicator has no problem, with them intact.



And you catch them and fix your methods, hopefully before failure.