case head seperation question


Michael R.
October 20, 2011, 06:26 PM
i have been reloading for about a 6 months or so. i have not reloaded enough to tell what the signs of case head speration look like. my lyman manual lists some photos, but they are in black and white. if anyone could tell me when a case needs to be discarded before case head sperates on the next firing, that would be great. also, how can you tell when the ring has become too bright?
p.s. try to include pics as well.

If you enjoyed reading about "case head seperation question" here in archive, you'll LOVE our community. Come join today for the full version!
Hay Creek
October 20, 2011, 07:55 PM
Check these links:

October 20, 2011, 08:00 PM
Many factors affect the lifespan of shell cases.

After three or four firings, the possibility of head separation should be a concern for you.

Study your own brass to learn how long it will last in your gun, and using your reloading methods.

I shoot .223 brass three times in an AR-15, and then I recycle it.

I have loaded .223 brass ten times, and not had it separate.
But, if you take 1000 cases, and shoot them through an AR, some of it is likely to separate after the third firing.
I shoot a lot of matches, and I don't want the score-penalty, and hassle, of a malfunction.
If you are just plinking, the inconvenience of a head separation is not much of an issue.

Somebody will be along shortly to say something that demonstrates that they don't know the difference between a head separation, and a head RUPTURE.

October 20, 2011, 08:00 PM
Gosh, I hope it isn't me!

Anyway, the quick & dirty way is:
Reach down inside the case with an L-bent paper clip or wire and feel for the stretch ring.
If you can feel it, it isn't too far from breaking.

Theres a good photo here:


Michael R.
October 20, 2011, 08:10 PM
thanks guys, now i have just have to get a tool to run through the cases. that shouldnt be too hard.

October 20, 2011, 08:21 PM
We have no idea what cartridge you are talking about, some are constructed more sturdily than others, but …IF you see a thin, bright ring around it…it is “suspect” at least.

Below is a bisected case from my .458 SOCOM, you can see how the case is thicker at the base, then tapers to the shoulder.

A closer look reveals no thinning (or nothing appreciable) after 6 loadings of maximum charges under a 405 grain bullet.

Case Thinning can occur in several places (especially with bottle necked cartridges), but a common spot is just above the case base or somewhere along the taper (often less than the way up).

An example of “Case Thinning” (not a SOCOM case) and a cheap way to check for it…is shown below:

If case thinning is significant….. you can get a tactile indication of it (actually FEEL it) by making a low tech tool from a paper clip or similar piece of wire.

Grind or file a sharply angled tip on the wire…..then bend it over 90 (making sure it will fit inside the case mouth).

Insert the tool all the way to the bottom of the case….(such that the “tip” drags along the side of the cartridge case as you withdraw it), if you feel the tool hang up or “bite”…. then assume the case has a step in it (has dangerously thinned due to stretching).

DO NOT use that case, throw it away!


Michael R.
October 20, 2011, 08:32 PM
i am reloading 30-06, 22-250, etc. but couldnt i use a caliper to measure the outside brass, or is it just on the inside where i can measure it

October 20, 2011, 10:06 PM
The thinning shows up on the inside as a rut in the brass, as shown in the pic. You cannot measure this on the outside. You must feel it on the inside, or use a special tool to measure it.

A discussion of case head separation with some good pics.

October 20, 2011, 10:10 PM
bigedp51's nice pic of a setup to measure the rut.

October 20, 2011, 11:34 PM

bigedp51's nice pic of a setup to measure the rut.


Not only do I take fantastic photos, I'm very good looking, exceedingly brilliant, and also very modest. :rolleyes:
(and I also have brown eyes) :uhoh:

Michael R.

Below are .303 British cartridge cases, from left to right, A brand new unfired case, fired once and fired three times.

On the third firing the case head above did not separate but look like the stretch marks your wife gets before the baby comes. :eek:

Below is "half" of a case head separation, on the back side you can't see its not cracked all the way and is only stretched.

This is what a factory loaded Winchester case looked like on the first firing, this case stretched .009.

Case head separations happen all the time and there is a "BIG" difference between this and a catastrophic case failure that dumps 50,000 cup back at your face. Below is a stuck case remover for .303 British cases that have had a case head separation.

Below is a Enfield rifle with a reloaded case that is about to separate (see my case that was reloaded three times above) The Enfield rifle had a piece of tablet paper wrapped around the receiver to show how the gas venting system works on the Enfield rifle.

Below the exposed paper showing scorch marks and the case head separation.

As you can see the paper was not blown to smithereens, the shooter was not injured in any way and the only damage might be brown stains in your underwear the first time it happens. :eek:

The trick to reloading is experience and having the tools you need to "read" your cases before and after firing. The Enfield rifle is a extreme example and the Enfield chamber was enlarged during WWI to make room for the mud of Flanders. Or chambering a cartridge is like parking a Volkswagen beetle in a blimp hangar.

When reloading and full length resizing you only need to push the shoulder back .001 to .002. If you push the shoulder back more than this the case will stretch in the base web area and this will lead to case head separations. This means you do not set the die up to contact the shell holder as the instructions state. The resizing die is made to push the shoulder back .002 below minimum headspace so all resized cases will fit in the chamber. If your rifles headspace is .003 over minimum you will be pushing the shoulder back .005 every time and the case will stretch and separate much sooner.

Nothing is written is stone, case head separations are governed by headspace, the size of the resizing die, how the case is constructed, meaning the diameter of the case and the case wall thickness.

Below is from Reloader Magazine

Please notice NO ONE died while testing these cases. ;) BUT safety glasses are a must for safe shooting of reloads. And new cases should be used when hunting for 100% reliability. All it takes is one defective case to screw up your hunting and you don't get a second shot if you have a case head separation when hunting large bears. :eek:

P.S. Don't even think about using old reloads and carrying pepper spray as backup for a ruptured case in bear country.

If you enjoyed reading about "case head seperation question" here in archive, you'll LOVE our community. Come join today for the full version!