Case Head Separation?

[Honest John]

I'm new to rifle reloading. Is this what incipient case head separation looks like?
The cases are .308, Winchester, only fired twice through a Kel-Tec RFB but I'm told that rifle is very hard on cases.
Thank you in advance.

 

[leadbury]

I strongly advise the use of a case micrometer gage of some form.I prefer the rcbs case mic. You measure a brass fired from your rifle to get a reference on how much to adjust your sizing die.This is critical for a semi auto gas gun cause it headspaces on the shoulder of the case.Too much "shoulder setback" and you can create over worked brass and excessive headspace which can lead to case head separation.Your full length sizing die can leave marks like you show,this is where the thick web meets the thinner case wall. A bolt action rifle can get by with just neck sizing usually. You just need to full length size a gas gun down a couple three thouasands so it cycles smoothly and does not "blow out" too much causing separation.Remember that brass flows from bottom to case mouth,the more firings the thinner the web base gets and the longer and thicker the mouth gets.Thats it in a nutshell, I really like to know what I'm doing when I'M adjusting my sizers.

 

[Curator]

John,

These do not look like incipient head separation, but rather the usual case expansion ahead of the case head. If you want to be sure, cut one down the middle and look for case thinning, or use the old bent paper clip to feel for a crack beginning on the inside of the case. Do a search on the subject in google images for pictures of what it looks like.

 

[Walkalong]

Could be, or could be what Curator noted.

Here is a thread on how to tell.

https://www.thehighroad.org/index.php?threads/incipient-case-head-separation.734058/

A couple of pics from that thread.

 

[edwardware]

Given the location, I suspect that's the transition from unexpanded head to expanded walls of the case. The sharpened paperclip will tell.

 

[Honest John]

Thank you, I suppose I should have looked for the thread devoted to the subject first.

 

[Walkalong]

Here is a .35 Remington showing

the usual case expansion ahead of the case head.

Check the inside and let us know what you find.

 

[Ironicaintit]

I have some 308s fired from an L1A1 (also rough on brass) that look identical to those. The line didn't show until they were sized. The dental pick test told me they were okay....very smooth, with no hang ups or roughness at all....but I sectioned one anyway, and to the naked eye, there was no thinning there.
How many cycles they will live through, I do not know

 

[FROGO207]

That sizing die will only size down so far on the brass and what is below (mostly in the shell holder) will not be sized any. That's OK as it is the web portion of the casing and does not expand like the sidewall above it. No rut found on the inside and you are good to go. Also I find my rings on bad brass are not perfect all the way around, rather they are a bit jagged when they are ready to separate on me. IMHO yours show a ring where the sizing die stopped shrinking the brass.