Shoulder/neck seperation

[oyster]

So how often does this happen? I had it happen on a round last week while hog hunting. Didn't realize what had happened until I got back home and took everything apart, cleaned etc. and it still wouldn't seat a loaded round. I thought maybe the chamber was really fouled so ran a chamber honing brush in it and out came the case neck broke off right below the shoulder. Aggravating to say the least when pigs are running everywhere and can't shoot. Then sneak up to within 10yrds of another group w/ out a functioning gun...
Thanks
Jay

[LRRPF52]

Have never had that happen.

Details about the rifle, barrel source, and ammunition please.

[kmon]

Have never had that happen.

Details about the rifle, barrel source, and ammunition please.

Agree with details to help.

I have never had or seen one of those, I have had 1 case head separation years ago.

New gun/barrel or have you shot it before?

Picture of the brass that separated, both parts might help as well.

[Klem]

Jay,

Sounds like case separation, or incipient case separation. Both are caused by too much headspace. 'Incipient' just means cases get overstretched and slowly weaken over a few firings, finally giving way.

I had two case separations from the same batch when I first started reloading 223. The cases were cut neat in half like they were hacksawed. The bottom halves were ejected normally but the tops needed some help to remove. It was caused by too much headspace - totally my fault. Squashed the cases too much when sizing so there was too much space between the case and chamber. Left a neat permanent circular line in the wall of the chamber where the heat/pressure was focused as it split.

Does your chamber now have a line marked on the inside wall coinciding with the split, that you can see or feel with a paper clip?

[grayfox]

If the break is up at or near the neck/shoulder junction...
I had a couple of those in 6.5 Creed, at the top of the shoulder, it came from excessive work hardening of the neck area during resizing.
Grendel is a lower pressure case but I guess it could still happen there.
Like others have said, pictures, info needed on rifle, barrel, load, the brass, pic of the separated case, etc. needed before we can have a good idea of what's going on.
Not discounting the others on case separation of course.

[VASCAR2]

[oyster]

This is an AR15parts.com upper. I've got around 1K or so rounds through it all factory ammo ( I don't reload yet). I had around 100 rnds through it since the last cleaning with no problems on function. It was a mixed mag of PPU HPBT and Hornady HPBT so hard to say which round it was and since it was night and I didn't know the cause I don't have the other half. I'll get a pic of the top tonight but it came apart right at the base of the shoulder just like a little funnel. BTW: after finding the issue and a through cleaning I went last night and killed six hogs, including a 325# sow with no issues, same ammo.
Jay

[oyster]

Also I just bought a bore scope to look at the chamber, hopefully it's not messed up.
Thanks for the replies.
Jay

[oyster]

Picture of neck

[VASCAR2]

[oyster]

That's what I'm hoping and I ran about a dozen rounds through it since and it's worked fine.
Jay

[kmon]

With the additional information I tend to agree with this

[Steve_evetS]

rupture case mag modification

I had 20 rounds of case rupture using wolf. thought it was a chamber issue. what was happening I think is an issue with mags. The case would get a sharp dent in the neck area when cycling. I only noticed this after I got back home so, I modified my mags. I haven't reshot yet maybe this weekend to see if the mags are working better.
mag1.jpg mag2.jpg mag4.jpg mag5.jpg