Case-Head Separation

[Hondo 60]

After 50,000 rounds (according to my reloading diary) I had a case/head separation.

Probably 10,000 of that is rifle (223) rounds.
The other 40,000 rounds would be various handgun calibers.

4x reloaded FC brass. 26gr of Varget under a 55gr FMJBT, OAL 2.230
I had no warning, nothing looked odd or different.
The rest of that box of 50, fired just fine.

I'll have to take a paper clip to the rest of that box.

But it was just weird, no warning, nothing looked out of the ordinary.

My question is, "Did I miss something?" or "do case/head separations happen with no warning?"

It's got me just a little spooked.

 

[LoonWulf]

I honestly cant say. Ive only had one experience with a casehead failure, not a full seperation. I had one on the first shot from some range brass i picked up, took the rest apart found a couple where the i sides were badly corroded and id missed them in the sorting.

 

[243winxb]

Case separations

My question is, "Did I miss something?" or "do case/head separations happen with no warning?"

Had one in 30-06 , never seen it comming and didnt know it happened, till ejection. Was in a Rem 760 pump. With 223 had body separations, caused by .014" shoulder set back. Look for bright shiny line. Also had necks crack, come off in 223. Some when firing. Others when FL sizing. Still not sure why? Its always good to know the history of the brass. Brass can be damaged on the first firing, if excessive headspace exists, even factory ammo. Chamber or cartridge slop is not good.

 

[cfullgraf]

With my 22 Hornet, case head separation happens with little or no warning. Sometimes, I'll see a bright ring around the base where the case is thinning but I've never been able to feel a thinning section with a bent paper clip. Neck sizing delays the failure and I toss the cases after four or five loadings to be safe.

With 308 Winchester fired in my M1A, I've been able to feel the thinning section in the base. These were the first cases that I've been able to feel. Kind of once you get a case with a thinning section, you know really know it and all other cases that you are not sure if the base is thinning, it probably is not thinning.

These mostly were once fired purchased cases that probably were originally fired in a machine gun. They are off my purchase list unless I absolutely know the original use of the cases.

Virtually all other bottle neck rifle cases that I load for, the cases fail for other reasons than case head separation, even cases fired and reloaded a few times in an AR then fired in a bolt gun. I've check lots of them in the past but do not any more.

But, I understand, other folks have other experiences.

 

[Grumulkin]

After 50,000 rounds (according to my reloading diary) I had a case/head separation.

My question is, "Did I miss something?" or "do case/head separations happen with no warning?"

Yes, you missed something and there was most likely a warning that you didn't look for, i.e., the paper clip method of checking, I check all bottlen necked brass for incipient case head separation after the first reloading.

By the way, unless a bright ring makes an incipient case head separation obvious, you need to check with the paper clip AFTER resizing.

 

[FROGO207]

cfullgraf I have had better luck with the bent paperclip/bent wire finding the separations if I sharpen the little bent portion to a sharp point then bend it. Now I use a dental pick that I have bent for this purpose and find it easier to hold in my fingers and turn as needed.

Sometimes you will get a few range brass that sneak in that are past useful life. As part of my first check when I sort my bottleneck brass I will look for the rut on every case each time. I now do not bother segregate by number of firings any more. I look for the rut, check for dents-dings, and neck splits. Then I process the brass and cull any that have easy primer removal when using the universal deprimer prior to wet cleaning. YMMV

 

[cfullgraf]

cfullgraf I have had better luck with the bent paperclip/bent wire finding the separations if I sharpen the little bent portion to a sharp point then bend it. Now I use a dental pick that I have bent for this purpose and find it easier to hold in my fingers and turn as needed.

Yes, I sharpen the bent end of the paper clip. If left the full diameter, it could easily glide over the thinning section without indicating a thing.

The dental pick is a good idea, better material for the purpose than a paper clip.

 

[rg1]

Having bought some 1000 round lots of once fired military brass, most all LC brass, I do the sharpened bent wire feeler method plus using a pen light to look inside the case. Out of 1000 rounds of once fired military I find anywhere from 5-10 up to even 25 cases that show stretch marks probably due to various military weapons in various conditions. I once bought a 500 round lot of commercial brass that had so many with bad stretching that I just scrapped the whole 500 cases. I long ago inspect every single case for evidence of stretching. Sometimes I find a case stretched to the point of separating just where the annealing stops with most stretched near the case head. I check all bottleneck rifle cases in every caliber. I even recheck after every firing. Luckily using my headspace gauges to adjust my dies I haven't had a separation since 1980 and even close inspection doesn't mean I won't, it just cuts down on the possibility. I get excessive though and I use the bent sharpened wire to feel the stretch mark, use a pen light shined through the flash hole to look inside the case, and even bought a cheap otoscope that doctors look inside your ears to inspect cases. And I wear a head magnifier with led lights for closer inspection.

 

[murf]

i believe harbor freight has dental pics on the cheap. great for checking case head separation and for general cleaning those hard-to-get areas!

murf

 

[Grumulkin]

Case head separation while mainly a problem with bottle necked case can also occur with straight walled cases use in high pressure applications.

 

[Walkalong]

I agree that the tool used needs to be relatively sharp or it can ride over the beginning of a rut. You also need to check all around and not just one spot. The rut tends to start on one side.

 

[Bart B.]

The single most common cause of case head separation (Walkalong, great picture showing one about to happen) is shooting a round in a chamber where there's too much head clearance (space between bolt face and case head when the round fires as its shoulder is hard against the chamber shoulder) for bottleneck cases headspacing on their shoulder or too much shoulder clearance on rimmed bottleneck cases. That "^" shaped part of the above pictured case is the pressure ring; it's work-hardened by bending when fired and resized moreso than any other part of the case.

That can happen with rimless bottleneck cases headspacing on their shoulder when the rifle chamber:

*has way too much headspace (near or at maximum specs) and fired cases are sized as much as possible; typically with the die set in the press so the lever "cams over" when sizing. In this instance, incipient or complete head separation happens with fewer reloads.

* is close to or at minimum specs for headspace and fired cases are set in the press so the lever "cams over" when sizing. In this instance, incipient or complete head separation happens with more reloads than above.

All of which is why the technique of full length sizing fired bottleneck cases should set their shoulder back about .002" for bolt guns and .003" for semiautos, levers and pumps. If you bolt action rifle's bolt face has been squared up, setback can be only .001", but you may need Redding Competition Shell Holders to find the one to use to keep case headspace spread to .001". Otherwise, there'll often be a case headspace spread of about .002" too .003" and head clearance will increase by that amount.

 

[Hondo 60]

The single most common cause of case head separation (Walkalong, great picture showing one about to happen) is shooting a round in a chamber where there's too much head clearance (space between bolt face and case head when the round fires as its shoulder is hard against the chamber shoulder) for bottleneck cases headspacing on their shoulder or too much shoulder clearance on rimmed bottleneck cases.

But I've had this rifle since 2010, with 1000's of rounds thru it, and this is the first time I've ever had c/h sep.

My guess is that the brass itself was not one of their best.

 

[Walkalong]

If the sizer was set up using work hardened brass and you switched to new or OF soft brass, the shoulder will be pushed back farther if the sizer is left as set.

 

[Bart B.]

Hondo,

How much are you setting fired case shoulders back?

Do you know what the chamber headspace is?

 

[Barrelgal]

I had a brand new piece of FC brass that blew the entire primer pocket seal all the way around. I was shooting a moderate development I'd been running for a number of years, part way into the second box one let go. The other 39 were fine and never a single pressure sign to include chrony verification.

Something that did catch my eye after I got home was the amount of case head expansion when compared to some of that same lot that hadn't been loaded / fired yet. I've stopped using any recently manufactured FC brass, I'm thinking it might be soft?

BG

 

[Swampman]

Case head separation while mainly a problem with bottle necked case can also occur with straight walled cases use in high pressure applications.

I guess that means the .44 magnum is officially a high pressure application.

 

[WVRJ]

This occurs as a result of too much headspace that happened sometime in the life of the case.Range pickups can be dangerous because of the unknown firearm they were shot in.Also,there are getting to be a lot of companies that are making el cheapo ammo that may not be of good quality,be it in the materials or the manufacturing process.Military/LE guns and ammo are most always on the loose side of headspace to keep guns running even when dirty,wet or neglected.Checking/sorting/choosing good brass will prevent it most of the time.