Case head separation: who's had it happen?

andyo5 · Sep 9, 2011

I need to learn about case head separation. Has it happened to you?
If so, I'd like to know...
1. What caliber?
2. What do you think caused it?
3. Are there pre-separation signs to look for?
4. What was the result? Was the gun damaged? Were you hurt?

I've never had it happen to me, but I have been noticing marks on my 357 magnum cases for awhile that I had assumed were scratches caused by the extractor. But I am starting to wonder. Look at the photo (please) and let me know if you have seen this before. It looks like a surface crack to me.
Thanks!

desi2358 · Sep 9, 2011

I've had case head separation in 303 british due mainly to case stretching with resized brass. No damage and not difficult to remove since I had a broken case extractor. The rifle was wartime production with an oversize chamber and reloaded cases neede to be neck sized only to avoid the problem.
I've removed headless cases from a few 22 rimfires as well for other people. Bad ammo or just a wornout gun in a couple cases. I have never had a problem with straight wall handgun cases in any caliber, they usually fail by splitting down the length of the case. Never saw a gun damaged by this either.
PS: that could be a crack in the case in your picture. I would cut it in two across the head so it could be checked and if it is a crack discard any others from that batch that looked suspect. Brass is cheap enough and it does wear out. If it did fail there I doubt it would damage anything but that chamber would be useless until you got it out.

flash60601 · Sep 9, 2011

I have experienced it in 303 Brit and 30-30Win, both being rimmed, tapered rifle cases, for the reasons desi suggested, having full-length resized cases too much.

But you are asking of revolver rounds.

Are you asking about the difference in diameter of the case about 3/16" ahead of the rim???

What you see there is the expansion of the case, ahead of the more solid case-head portion of the case, where the brass thins to the nominal wall thickness. It is expanded in the firing there, whereas the case-head section does not expand its diameter appreciably, and thus creates the different appearance. Not to worry, most cases do this to one degree or another, and does not affect reloading or shooting.

Or are you asking about that little dark line that goes around the case, about .020" ahead of the extractor groove?

If that, check the mouth of your chamber for burrs, or on the back of the extractor-star. That would seem to me to be the most likely culprit for that. Does it show up on every fired case, or only on cases from one chamber? Is it apparent on cases from all manufacturers or just one?

What gun are you using??? Ammo? Factory? Reloads? That's important information to those who could be of help.

And if you were using it in a rifle for Cowboy stuff, I imagine the chamber may have a slight chamfer which could make that kind of imprint.
Flash

cochise · Sep 9, 2011

Yes I have. I was shooting reloads in a Marlin rifle and once in my S&W pistol, both .44 magnum. The rifle case separated completely and came out with a bore brush. The handgun was a partial separation until I fumbled with it in my hand. Old brass finally gave out. Over 20 reloads. No damage, no problems. I only use full charge loads in the newer brass from now on.

I think you do have a start of case separation. How many reloads in the case?

tops · Sep 9, 2011

Never had one with a pistol but did have one with a 22-250. A .30 cal. bore brush jerked it out. No damage. Larry

WR Moore · Sep 9, 2011

That mark on that case may be where your sizing die stops. If so, your case displays evidence of possible case head expansion.

Case head expansion has two possible causes: brass too soft or loads too hot.

I'd suggest miking a new, unfired case just ahead of the rim and recording the reading. Do so again after firing. If the case head area expands more than about 0.0005 inches ( 5 ten thousandths of an inch), you're in troubled waters. I'd try a different brand of brass and/or reconsider my loading data.

Dragon88 · Sep 9, 2011

andyo5 said:

That looks sketchy to me, but without having the case in hand for inspection it's hard to say. How many times have these cases been reloaded, and with what type of loads?

Make a tool out of wire to inspect the inside of the case. Basically a length long enough to reach down in the case, and curved slightly on one end. Slide the end along the inside of the case where that mark is, and see if you feel a valley. If so, that is almost surely eminent case head separation.

Fishinfool · Sep 9, 2011

Well, here is what happens when someone places a "FX Simulations" barrel on an active duty gun, and that gun is able to chamber and fire a real round....

The FX barrel is designed to fire sub caliber training rounds, and has a bore of about .25 caliber, or so. Should NOT be able to chamber real ammo. This one did. I can only imagine the pressure...

The shooter on the line said he "thought it felt funny", then noticed the magazine had droped out. The case head blew out, damaging the second round in the magazine, and that was it. The barrel and the S&W 59 were undamaged.

Larry

scattershot · Sep 9, 2011

That sure looks like an incipient separation to me. I'd bet if you squeezed that case with a pair of pliers, it would break right at that line. What kind of brass is it, and how many times has it been reloaded? What load?

To answer your question, though, I have had a case separation in a 45/70. I was experimenting with fillers in the case, and had loaded a mid range charge of 2400 under the bullet, after filling the case with Cream of Wheat. Bad mistake. You can get away with fillers with black powder, but not, apparently, with smokeless.

It was purely my ignorance that caused it, I wasn't hurt, but there's a barely perceptable ring in the chamber of that rifle to this day.

Alk8944 · Sep 10, 2011

andyo5 said:
I need to learn about case head separation. Has it happened to you?
If so, I'd like to know...
1. What caliber?
2. What do you think caused it?
3. Are there pre-separation signs to look for?
4. What was the result? Was the gun damaged? Were you hurt?

I've never had it happen to me, but I have been noticing marks on my 357 magnum cases for awhile that I had assumed were scratches caused by the extractor. But I am starting to wonder. Look at the photo (please) and let me know if you have seen this before. It looks like a surface crack to me.
Thanks!

That is a sizing mark from running your cases all the way into a carbide sizing die. That is why the case is bright right up to the line.

Look at your own picture. About 1/16" ahead of the line you will see where the case is expanded slightly larger than the bottom osf the case. This is where the "web" of the case is. the transition from the solid head to the sidewall of the case. The line appears approximately half way down on the solid head, cases DO NOT separate at this point!

When you size your brass you feel a hard "bump" at the end of the downward stroke of the press handle, don't you? This is where the solid head is being forced into the sizing ring. Not only does this size a portion of the case that should not be sized, but if you keep it up you will break the carbide sizing ring in the sizing die.

I might be stepping on some toes, but I can tell you that anyone who saw a problem with this probably has never loaded a cartridge in their life, and their only "experience" is reading magazines and forums like this one.

fredj338 · Sep 10, 2011

I have had near misses w/ a couple rifle rounds. I had one a few weeks ago in a G32 in 357sig, case head pulled out & lef the shoulder/neck in the chamber. Pushed it out w/ a bronze brush & went back to shooting.
Most head seps are excessive headspace issues or brass that doesn't fit the chamber well or a bad piece of brass (357sig).

lebomm · Sep 10, 2011

Rossi M92 Puma in .357. Blazer aluminum case separated due to natural action elasticity, less in case. Came out w/a bore brush.

Larry

Dragon88 · Sep 10, 2011

Alk8944 said:
I might be stepping on some toes, but I can tell you that anyone who saw a problem with this probably has never loaded a cartridge in their life, and their only "experience" is reading magazines and forums like this one.

And what's your experience from, watching Youtube videos?

W.E.G. · Sep 10, 2011

This is a case head SEPARATION:

This is a case head RUPTURE:

W.E.G. · Sep 10, 2011

I've had bunches of case head separations in the M1A and AR15.
Always harmless, except for often having to fish the front half of the case out of the chamber. A chamber brush usually handles the task smartly.

W.E.G. · Sep 10, 2011

A case head RUPTURE is usually a catastrophic event which blasts gas, and bits of molten metal, back into the shooter's face. A rupture is a very bad thing.

A rupture can be due to an out-of-battery discharge, or a failure of the base of the cartridge.

What happen???

LoboGunLeather · Sep 10, 2011

I've experienced case head separation in .45-70, .30-06, .30-40 Krag, and .218 Bee. Always with handloads, always with cases that had been loaded and fired with full charges more than 3 or 4 times. Separations have occured during extraction of the fired case, but more frequently in the sizer die when resizing. Both can be a PITA to deal with.

For years now I have kept track of each batch of brass, starting with either new factory ammo or new brass. I reload with full charges only 3 times, then the brass is segregated out for use only with reduced loads.

Rifle cases get scrapped after 10 loadings.

On the other hand, I have lots of .38 Special, .45 ACP, and 9mm brass that have been loaded and fired 20 times or more with modest practice loads. Case mouth cracks, yes, but no head separations. I wouldn't try that with magnum or +P loads.

MTKTM · Sep 10, 2011

I've handloaded for 40some years and have never once seen a case-head separation with a straight walled case like most handgun rounds or the 45/70, etc. I cannot deny the photographic evidence submitted by cochise and other posters here, learn something new every day, just haven't ever had that happen personally. Straight walled brass failures seem to consist of vertical cracking around the case-mouth as the metal fatigues and hardens due to repeated reloading and resizing/crimping.

Bottle-neck rifle rounds are another matter. The worse offenders in my experience are tapered rifle rounds like the 300 and 375H&H. A few years back I acquired a Ruger No. 1 in 9.3x74R, which is a very long tapered round, and I'm watching that brass very carefully. While usually not a big deal, a case-head separation can be nasty and is best avoided if possible.

andyo5 · Sep 10, 2011

Alk8944 said:
That is a sizing mark from running your cases all the way into a carbide sizing die. That is why the case is bright right up to the line.

Look at your own picture. About 1/16" ahead of the line you will see where the case is expanded slightly larger than the bottom osf the case. This is where the "web" of the case is. the transition from the solid head to the sidewall of the case. The line appears approximately half way down on the solid head, cases DO NOT separate at this point!

When you size your brass you feel a hard "bump" at the end of the downward stroke of the press handle, don't you? This is where the solid head is being forced into the sizing ring. Not only does this size a portion of the case that should not be sized, but if you keep it up you will break the carbide sizing ring in the sizing die.

I might be stepping on some toes, but I can tell you that anyone who saw a problem with this probably has never loaded a cartridge in their life, and their only "experience" is reading magazines and forums like this one.

ALK, You are right. I checked for an internal ridge; and finding none, I sectioned through the case about 1/4" forward of the apparent 'crack'. There was no evidence of thinning, ridging, or cracking inside the case. That mark is below the case walls, in the area coinciding with the solid case head.
My sizing die is adjusted all the way down, until it just contacts the shell plate. Do you recommending backing it off?
By the way, thanks to all who responded with a post.

Alk8944 · Sep 10, 2011

Dragon88 said:
And what's your experience from, watching Youtube videos?

No, smart a**, it's over 50 years of practical loading, shooting, much of it competitive, and something in the vicinity of 1 million rounds. Not a single round on a progressive, and since quite a few years before Carbide sizers were commonly available.

If you have any questions about my conclusions read Andy05's last post just above.

Case head separation: who's had it happen?

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