Which is the better indicator of impending head separation?

Charlie98 said:

Something as simple as the plastic ammo box can leave a ring like that on brass.. . .

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See this ^ ^ ^ all the time

Beside using a pick or bent paper clip, one can usually see with a light inside the case, the impending incipient case head separation.

Ranger99 said:

See this ^ ^ ^ all the time

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I was laughing about this as my 308 now has a sizing ring at just the wrong spot that gives the appearance of this problem. I had inspected the brass 2 times already so I knew it was a non issue but another reloader at the range will be like hay bro.....

edwardware said:

I think gas venting out the back is a near certainty in the case of a head separation. . . but there's very little chance of it (case head separation) hurting you.

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This may depend on the action of tne rifle. A Rem 700 is safer then a Savage. Savages have dislodged the extractor out of the bolt during a case head separation.

My Rem 600 243 bolt shows pock marks for some defective primers, fired years ago. No gas hit me in the face. Not so with the same bad primers in my 1903 Springfield.

243winxb said:

My Rem 600 243 bolt shows pock marks for some defective primers, fired years ago. No gas hit me in the face.

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You've provide a good example. The gas that cut those pits vented out the back. . . but your action includes sufficient gas management to spare you even noticing. Such had been my experience with head separations.

edwardware said:

You've provide a good example. The gas that cut those pits vented out the back. . . but your action includes sufficient gas management to spare you even noticing. Such had been my experience with head separations.

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Even without a single head separation I have seen odd things with “gas cutting” like this 1911 firing pin stop from shooting aluminum factory loaded cases (a lot of them) gas made it all the way from the breechface through the firing pin hole to erode the firing pin stop!

That area is also where some of the drill press mounted case trimmers leave a mark to when trimming.

Like said if you can not feel it with a fine pick, it's not there. Depending on cartridge size a bore scope could be used. I use a orthoscope to view inside small small areas without cutting them open.

AJC1 said:

If you find that they are bad I would love to get one for training, as I have never felt a bad one and I'd use it to learn.

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I may have one I can send you. Will have to look the next time I'm in my shop.

jmorris said:

. . . like this 1911 firing pin stop from shooting aluminum factory loaded cases. . .

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I would not have though the breechface would survive intact long enough for the FP stop, 1.5" away, to erode that badly.

And that's the outside (hammer) face of the FP stop. Are you sure that's really gas cutting?

barnfrog said:

So I just full-length sized a bunch of Remington .243 cases that have been reloaded once. The powder charge was near max, a couple tenths of a grain below where I had seen pressure signs when I developed the load. A few of the cases have a ring round them slightly more than half way from the head to the shoulder.

View attachment 988650

When I run a bent paper clip along the inside of the case wall it feels absolutely smooth. Should I be erring on the side of extreme caution and tossing these few that have the ring, or trusting my fingers that there is no serious defect?

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Just curious.... @barnfrog what tool are you using to chamfer/debur? I used to get that ring a lot when I used the Lee hand tool to debur.

If you have a borescope, you might try using it. If not, use the paper clip sharpened to a chisel tip. If there is an impending separation there will be no doubt when you drag the chisel tip thru the thinned groove/channel.

Check the orientation of the "clip" in Walkalong's picture on page 1.

That looks too high to be a case head separation. The ring looks like something from a trimming collet or a perhaps a die. If the paperclip test and a small pen light don't reveal an insipient separation, review all of your case prep stages to consider what else it might be.

Since it's germane to the discussion... someone mentioned case head blowouts... this is what it looks like...





...and the cutaway...



These were fired in my M1a... they blew the magazine out and left a pile of ammo and mag guts on my feet... but thankfully nothing else. After a LOT of discussion and debate, I have concluded the surplus brass was compromised in some way... either it was brittle to start, or it was exposed to something after it was turned in and sat that weakened the brass. This was LC 05, but I had the same type case head fracture in other headstamp LC brass, but from the same 'once-fired, processed' lot.

barnfrog said:

Thank you all. As usual, had I given it some thought I MIGHT have come up with the rather obvious idea of cutting one or two open to see what the deal is. I'll try to do that in the next day or two and post some pics. AJC1, you're more than welcome to any that have an actual defect.

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I have one question. Did you sharpen your paperclip? An unsharpened one can give a false negative.

barnfrog said:

I did not at the time, and fortunately it did not result in such a result as you indicate it could have. However, I have since sharpened it for future use.

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I read that in a reloading manual. Since I'm here headed I had to test it.
Since then I've learned not to question everything in the how to reload sections.

first your eye, then a paper clip.

Charlie98 said:

Since it's germane to the discussion... someone mentioned case head blowouts... this is what it looks like...

View attachment 1003337

View attachment 1003338

...and the cutaway...

View attachment 1003339

These were fired in my M1a... they blew the magazine out and left a pile of ammo and mag guts on my feet... but thankfully nothing else. After a LOT of discussion and debate, I have concluded the surplus brass was compromised in some way... either it was brittle to start, or it was exposed to something after it was turned in and sat that weakened the brass. This was LC 05, but I had the same type case head fracture in other headstamp LC brass, but from the same 'once-fired, processed' lot.

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This case broke through its case head during a 300 yard rapid fire in a NRA Across the course match. It blew out the magazine from the AR15. And this will bake your noddle, the next round fed into the chamber! The shooter was un injured, just the magazine was a bit mangled, and the rifle was shootable after the jam was cleared.

The case came from Scharch, it was from pull down military surplus.









Another shooter at the match told me he had similar problems with 5,56 military brass acquired from Scharch.

What I am going to say, the common thread is military pulldown brass. And I am going to claim, that the only reason the military culled that stuff from its inventory was because an Ammunition Technician had gone through that lot of ammunition and found gunpowder deterioration. It may have looked like this



and it will lead to problems like this



When gunpowder deteriorates it releases NOx, some of which is converted to NO2, nitrogen dioxide, and some of that will convert to nitric acid gas if it encounters a water molecule. Which there is some in the air in the cartridge case. And those reactive chemicals will cause brass to deteriorate.

Awesome! @barnfrog Glad I could help! I knew those score marks looked familiar!

Making me wonder of the surplus brass I cleaned and if I might have a failure like that. Hmmmm.

Slamfire said:

This case broke through its case head during a 300 yard rapid fire in a NRA Across the course match. It blew out the magazine from the AR15. And this will bake your noddle, the next round fed into the chamber! The shooter was un injured, just the magazine was a bit mangled, and the rifle was shootable after the jam was cleared.

The case came from Scharch, it was from pull down military surplus.

View attachment 1003372

View attachment 1003373

View attachment 1003374

View attachment 1003375

Another shooter at the match told me he had similar problems with 5,56 military brass acquired from Scharch.

What I am going to say, the common thread is military pulldown brass. And I am going to claim, that the only reason the military culled that stuff from its inventory was because an Ammunition Technician had gone through that lot of ammunition and found gunpowder deterioration. It may have looked like this

View attachment 1003376

and it will lead to problems like this

View attachment 1003377

When gunpowder deteriorates it releases NOx, some of which is converted to NO2, nitrogen dioxide, and some of that will convert to nitric acid gas if it encounters a water molecule. Which there is some in the air in the cartridge case. And those reactive chemicals will cause brass to deteriorate.

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I once had a brand new case fail in similar fashion while working up loads. Was loading up using customer supplied brand new brass when it occurred.



Was far enough away from published maximum loads in charge, I decided to section another case that had not been loaded.



After that I switched over to once fired brass I had and finished working up the load. So there is a chance old age was not the only issue.