Case neck separation?

[243winxb]

Never heard of neck seperation.

Brittle brass. Over the years , i had problems with 5.56 LC brass and some Federal. https://www.thehighroad.org/index.p...aused-this-neck-to-part.885428/#post-11862076
See my posts.The OPs brass is ok to use. Imo.

 

[Dusty Stevens]

Brittle brass. Over the years , i had problems with 5.56 LC brass and some Federal. https://www.thehighroad.org/index.p...aused-this-neck-to-part.885428/#post-11862076
See my posts.The OPs brass is ok to use. Imo.View attachment 1242175View attachment 1242177

They even make a tool for it. Happens all the time.

 

[rijndael]

A nylon pistol brush, like the ones Glock puts in every case, works really well.

 

[divingin]

Brittle brass. Over the years , i had problems with 5.56 LC brass and some Federal.

Had something similar with some 308 I was given. Cleaned it up (might have had to pull them down first - don't remember now), lubed, ran them into a FL sizer, and about 8 of the 10 I did came out like this:

[Sorry; that pic came out bigger than I expected]

Needless to say, they all went into the brass for recycle bucket. (I measured a few before tossing; they were running about .020-.030" over SAAMI max length.)

 

[Webster]

Brittle brass. Over the years , i had problems with 5.56 LC brass and some Federal. https://www.thehighroad.org/index.p...aused-this-neck-to-part.885428/#post-11862076
See my posts.The OPs brass is ok to use. Imo.View attachment 1242175View attachment 1242177

Stress corrosion rather than work hardening???

 

[Webster]

Had something similar with some 308 I was given. Cleaned it up (might have had to pull them down first - don't remember now), lubed, ran them into a FL sizer, and about 8 of the 10 I did came out like this:

View attachment 1242260[Sorry; that pic came out bigger than I expected]

Needless to say, they all went into the brass for recycle bucket. (I measured a few before tossing; they were running about .020-.030" over SAAMI max length.)

Is that a crack in the extraction grove? Very strange. Cannot be work hardening in this area.

 

[243winxb]

Stress corrosion rather than work hardening???

Thats one reason.

There are many reasons why it becomes brittle.
1. Not annealed correctly at factory. Cheap ammo will get less annealing.

2.Solvents or liquid cleaning agents. Annonia or vinegar. Residue from first firing left in brass.

3. Dies over working the brass. Some new brass already has a donut. 223/5.56 Bushing die or neck turning solves the problem. Neck turned brass can be loaded in my RCBS standard FL die.

4. Overly large chamber that allows brass to expand more then normal. This over works brass.

5. Dezincification
http://benchrest.com/showthread.php?58344-Dezincification-of-Brass-Liquid-cleaners

All may produce Brittle Brass. Imo.

NOTE: I am not a metallurgist.

 

[243winxb]

They even make a tool for it. Happens all the time. View attachment 1242245

The next round chambered will jam into remaining neck. Easly extracted.

 

[rogn]

Different sizing dies on loading machinery, varied chamber among random firearms, all can lead to different carbon rings.
Cracks, see list above about hardening and just add work hardening.
Any brush bigger than bullet diameter if applied carefully depth of neck will pop the piece out. Just don't reverse in bore. Nylon brush is insurance.

 

[divingin]

Is that a crack in the extraction grove? Very strange. Cannot be work hardening in this area.

On mine? No, that's probably just lighting. I didn't notice anything odd on the case below the neck.

As far as I know, these were stored unloaded, so I doubt it had anything to do with dissimilar metal corrosion or anything like that. I took it as an advertisement for annealing (and an argument against using brass that someone else is getting rid of.)