Impending Case Head Separation

[SuperBreed]

Howdy, I am looking for those with more experience hand-loading 45-70. I just cleaned some brass to reload and noticed what appeared to be the signs of case head separation on a few case. I went through the rest a pulled the ones I thought had the early signs.

What I am going off is the line all the way around the brass just above rim. The line is so faint that if not in the right light you could miss it. I have included pictures of the cases in question. My question is could these be loaded again or should I just chuck em.

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[Longwalkhome]

Looks to me like it's just the mark left where the resize die stops. I would still use them until it's a very shining mark.

 

[SuperBreed]

I kinda though that too at first, but why only on like 6 out of 30 pieces. Any time I've had the sizing mark you are referring to, it is on every piece I put through the die. Think I may just cross section that piece and see what it looks like on the inside to be safe. These have more than a few times fired, that's another reason I'm leaning towards separation and not the die leaving marks. I'll update later tonight.


Also the pictures don't show the line very well. You have to really zoom in the see it.

 

[Certaindeaf]

Just a die rub. I've never had to trim straight wall cases that started life within spec.

 

[ma96782]

You could try the paperclip test. Truthfully though, I don't do things that way.

How I do it......
Speaking of my M1a and .308 W reloads.

Assuming that you've acquired your brass together (or the loaded ammo was made with the same lot #). So then, I'll reload my brass in 100 round lots. The entire lot stays together and goes through reload cycles together. So, say that 5 out of 100 fail (or show the signs of a case separation coming). Yeah it's time. So, I'll condemn the entire lot of brass. FYI, usually it happens on the same cycle. Of course, you could make up your own magic number as to when you'll call it quits for the lot.

Maybe once (one case) is enough? Yeah.....it sucks, when the rest of the case is "stuck" in the chamber.

Aloha, Mark

 

[drstrangelove]

Straight walled cases don't grow… bottleneck brass does. There is no reason for ICHS here. That's a mark where the die stops resizing.

 

[whiskeybill]

Rimmed straight wall cases do "grow", or stretch. and that is why they must be trimmed on occasion. Unlike rimless bottle neck cases that headspace on the shoulder, rimmed cases headspace on the rim. Rarely if ever do straight walled rimmed cases separate. Split and crack lengthwise somewhere on the case wall, yes. Most reloading manuals discuss case separation and headspace issues. It's even illustrated in photos and drawings.

 

[bcp]

From:

Incipient Case-Head Separation — How to Detect the Problem « Daily Bulletin

We are re-publishing this article at the request of Forum members who found the information very valuable. If you haven’t read this Safety Tip before, take a moment to learn how you can inspect your fired brass to determine if there may be a potential for case separation. A case separation can...

bulletin.accurateshooter.com

Bruce

 

[Pepe-lepew]

It is either a die rub or the transition from where the case expanded to the chamber wall and the minor diameter at the case head. Not all the case expands to the case wall near the thicker base.

If it was case head seperation, you will see a necking line on the inside.

 

[Koda]

In my experience a pressure ring on the outside is fine and just an impression where the case wall thickness becomes thinner so it expands faster. This happens normally on all rifle cases.



A pressure ring on the -inside- of the case is what you want to worry about, a clear sign of case head separation. A ring on the inside can be felt with a bent paperclip test.

 

[P7M13]

My guess, it's the chamber.
Here are pics from my 45/70
The ones that look like they have impending rupture (right side in photos) are unprocessed after their third firing. The ones that look shiny and new on the left have been fired 2x, deprived, resized and tumbled.
I remember seeing those "lines" after the 2nd firings.
If you examine the brass at different angles, the bulge tells me they are expanding in my chamber.
I don't think they're stretching, though, or you would have to trim.
I haven't annealed any 45/70 brass, but if I did, it would be at the bulge and at the case mouth.

Are you shooting 350"a or 405's?
I shoot 405s and the chamber pressure is lower.

 

[SuperBreed]

Thanks everyone for the replies.

I was aware of the paper clip trick to check for separation, once I didn't feel anything, I wasn't sure what was causing the ring.that's when I posted my question.
Because of some replies here, and further research myself, I agree that the ring is do to expansion of the case in the chamber. Gonna finish loading these up tonight.