Case head Separation…in Sizing die

[T.Rhodes]

This was a ‘first’ for me. Had a case head separation in the sizing die…glad it waited until it fired and not in the rifle.

It’s a 6.5cm Lapua brass…I thought Lapua was “bulletproof” but it’s on me, I haven’t been diligent about counting firings…in the past. Learned my lesson.

I’ve used the paper clip to try and find that rim but never successfully. The pictures show how low in base the separation was. Also a borescope shot of the inside of another case on its way to trash can.

From outside of a bad case there’s just the slightest color change at the future separation line. No detectable ridge that can be felt.

Anyway, thought I’d share that. Still have upper portion of stuck case in the die. Was using OneShot case lube…I guess not enough.

 

[Rocketvapor]

Could you cut the case to show a profile of the head and web?

 

[T.Rhodes]

Does this show it better?

 

[Rocketvapor]

Yup, you was lucky.

Was hoping for a cross section thru the web.
Sort of like this;


This is one of my 22 Nosler cases.

 

[T.Rhodes]

Might try to get one tomorrow.

 

[K22]

Never saw one that low but I imagine anything is possible.

All the ones I observed were at least about 1/2 inch above the case head with a faint fatigue line clearly visible. Thanks for sharing.

 

[K22]

Forgot to ask, were you monitoring fire case head space versus the sized amount? If so, how much were you pushing the shoulder back?

 

[T.Rhodes]

Forgot to ask, were you monitoring fire case head space versus the sized amount? If so, how much were you pushing the shoulder back?

Yes, from fired to sized .002 to .003” bump.

 

[Fast14riot]

I would measure case diameter at the .200" line of fired vs sized. That seems like excessive sizing for it to part there.

 

[Rook 6]

I would measure case diameter at the .200" line of fired vs sized. That seems like excessive sizing for it to part there.

This would be intersting to know. I’ve never heard of a case head separation with no divot ring but seems to be the scenario here. There certainly doesn’t seem to be a headspace issue. In for the info.

 

[6.5 forever]

So the upper case body is still in the die?
Could lube be part of the problem?

 

[Rocketvapor]

Case stuck in die probably saved you some anguish.
Just think if case had come out of the die.

 

[Rsadams]

You should probably buy a few lottery tickets...

 

[T.Rhodes]

Yup, you was lucky.

Was hoping for a cross section thru the web.
Sort of like this;
View attachment 1570045

This is one of my 22 Nosler cases.
View attachment 1570049

I did one case and it shows the beginning of a thinning at the base. This one may have lasted longer...we'll never know.

I didn't get it cut exactly in the center so the flash hole isn't seen - but it does shows thinning of the case wall.

 

[Rocketvapor]

thanks.

 

[T.Rhodes]

So the upper case body is still in the die?
Could lube be part of the problem?

Yes. Trying to extract it but no success yet. I used One Shot case lube but either didn't use enough or....

This was a Redding FL body die.

 

[rijndael]

I hate to say it, but "One Shot" .... I KNEW IT!

 

[T.Rhodes]

Here's a better shot of the other half of the case I cross sectioned.

 

[rijndael]

I wonder if sacrificing a case, now and then, is a better way to go than just the paperclip method.

 

[Rocketvapor]

I think taking 600 to 800 grit paper longitudinally over the area to highlight impending separation line might show this.