Early signs of case head separation

[243winxb]

May separate in the middle of the body also. .014" head clearance will do 5.56/223 brass.

 

[XTR]

In my experience 223 brass separates much higher than 308. Kinda like the picture above

 

[deadidarren]

Yes.
Shoulder 'bump' seems to have become a 'step' in many peoples reloading process.
Shoulder bumping to me (I'm talking Bolt actions) is a remedy to correct a fault.
The bolt is stiff opening for example.
Making 'bumping' a part of your reloading routine is asking for case failure. I try to work the brass as little as possible. Should the bolt have a stiff lift well the push the shoulder back some. It's not a set number.
Your cartridge fires. The brass (with the help of 50,000 psi) fills the chamber. The headspace (which is IN the chamber) is from the closed face of the bolt to a point on the shoulder (called datum line). If you have excessive headspace the brass reaches these two points by stretching. (I'm not mentioning spring back). Now if the charge was hot enough one can imagine lifting the bolt may be a bit stiff. This case has stretched far enough to cause this. By 'bumping' the shoulder back a bit it will now chamber nicely. To constantly 'bump' ( for no reason) this shoulder therefore increasing headspace your brass's life is shortened. The brass will do the stretch thing only so much.
Some cartridges are much easier on brass than others. I have a 222 with maybe 25 reloading's on it. Never a 'bump' needed.

I wholeheartedly agree I have lapua 260 Remington brass here some of it on its 15th loading and it still slides into the chamber easy the bolt handle just thumbs down like virgin brass only ever neck sized .

 

[Martin52]

The purpose of the post was just to suggest that evidence of brass 'wear' may be available much earlier than expected on low numbers of firings by inspecting the inside of a case when there may be none of the usual signs on the outside.

These particular cases started life at 1.629, grew to 1.6315 and were FLS to 1.630. They were fired in a palma rifle, Barnard action, tight chamber. Load as posted above.

Out of a batch of 50 cases, only 4 showed the signs in the opening pic's. I will be monitoring the other 46 as they are fired in future.

Before Teslong, most would have just been alerted to upcoming head separations by signs on the outside of a case (amongst other signs) but now we have the ability to check inside the cases.

 

[Webster]

View attachment 1329156View attachment 1329157View attachment 1329158

These pics show early signs of case head separation and are taken inside the case at the .200 line.

There was very little indication on the outside of the cases other than a very fine line that could have been easily missed.

To be safe, I looked inside with my borescope.

One image shows a shiny line/crack developing, the other two show dark lines that circle the interior at the .200 line.

These are 3 x fired 0.308 large rifle primer cases. The load was 43 gr IMR8208 behind a Berger 155.5 projectile (COAL 2.91). Shoulder setback was minimal from first firing, 0.001. BR2 primers.

Posted just for general interest.

There is no reason for a color change if the brass is being stretched. I still think it could be a stain. Easy to resolve.

 

[SeabeeKen]

Since no two chambers are the same, and new brass is gonna vary, Id create a false shoulder on new brass for fireforming. A snug bolt closure will ensure its tight in the chamber front to back. Once fire formed, Id bump as usual. I do this with all 5 of my ackleys after losing 2 cases in a 257AI. Never an issue since.