Do I throw away this whole lot of brass?

[Troutslayer2]

Well I am going to go with bad batch of brass. My measuring is meticulous. I think I had 1 piece separate like this on the very first firing. I have not had the best luck with Nosler brass. I have not had the best week of shooting either. I noticed that one of my suppressors has bulges in it from the last time it was used and I realized today that one of my scopes is not holding zero or there is something wrong with the mount.

 

[L.Sherm]

As you might realize now Nosler brass is soft, throw it in the garbage and get some Peterson 280AI brass

 

[Troutslayer2]

As you might realize now Nosler brass is soft, throw it in the garbage and get some Peterson 280AI brass

Way ahead of you. I have a 100 pieces with 1 firing on them in the tumbler now. I was just playing around with some Hammer bullets I have lying around, doing some load development. I didn't want to cut into my stash of Peterson for that.

 

[Mikecr]

If you're getting a lot of stretch on first firing then you need to manage that.
Obviously -it's not a tight chamber.
Back off on load for 1st firing, and force head spacing with jammed bullets or false shoulder.
Do not oversize your brass, but creep into shoulder bump with cases that are fire formed to stable dimensions of your chamber.

 

[243winxb]

Brass can be damaged on the first firing.

I wish I had a brand new piece to measure against a fired one

More then .010" difference, to much stretch on fire forming.

May need a false shoulder to fire form new brass.

 

[Tiny Tim]

Scrap it! What kind of damage might you be doing to your action/chamber with the release of gasses as evidenced by your pictures? Not to mention your personal safety. Start over and take the advice given here, particularly @Mikecr and @243winxb

 

[nkyshooter]

Was your "first firing" a forming load using 280 Rem cases as opposed to 280 AI? If so, then it seems you are experiencing case head separation resulting from excessive headspace between the standard 280 and the AI dimensional differences.

The "jam" for fire forming may be a hard requirement for your particular rifle ... I use the jam method when forming my 260 AI brass but I also know there are some subtle differences with the 280AI as compared to other AI's since SAAMI made some modifications beyond the straight AI approach when they standardized it - someone with way more knowledge than me will be much better equipped to provide more on that if you want.

I'd be interested to hear more information about the rifle itself ... brand? ... all factory? ... aftermarket barrel? ... who headspaced it? By definition, 280 Rem (non-AI) saami spec is safe (i.e. won't result in case head separation) when fired in the AI chamber ...

Based on what the above info is, I may be leaning even further towards a potential headspace problem that will not go away with changing out the brass ... I'd want to get this figured out on the "less valuable" nosler brass before using or fireforming on the more expensive stuff ... not to mention the safety concern ...

Just my $.02 ...

 

[Mikecr]

The 280Rem neck-shoulder junction shows in my software as 2.199".
Drawings for 280AI show it at 2.182".
17thou shorter.

So the AI chamber should be considerably shorter at neck-shoulder, causing an interference fit(negative headspace) with new cases.
On firing this neck-shoulder should pull back a bit with increasing of shoulder angle, but there should be no body stretch back to boltface as it the case head should have been hard against the boltface. This is normal & good.

Here, either the chamber is wrong or there has been heavy die sizing prior to firing -that's muddling up the design plan.

 

[Tiny Tim]

The 280Rem neck-shoulder junction shows in my software as 2.199".
Drawings for 280AI show it at 2.182".
17thou shorter.

So the AI chamber should be considerably shorter at neck-shoulder, causing an interference fit(negative headspace) with new cases.
On firing this neck-shoulder should pull back a bit with increasing of shoulder angle, but there should be no body stretch back to boltface as it the case head should have been hard against the boltface. This is normal & good.

Here, either the chamber is wrong or there has been heavy die sizing prior to firing -that's muddling up the design plan.

.017 is alot of interference. Would the bolt close? Or is there enough angle in the neck/shoulder junction to allow this?

 

[Gater]

The only brass I full length size is for my AR-15 and M-1A the AR cracks at the mouth after about 10 loadings the M1A after about 5 or so it will show signs of separation at the head once a couple start showing signs then it gets scraped. When it comes to my .223 volt gun I only neck size and have never annealed any of them some have been loaded 15 times all of them go in and out with ease and that gun literally shoots dimes at 200

 

[Huggy]

I have been messing with some brass that I know is on it's last loading. I have a bunch more of it prepped and ready to load but maybe 10% of them are coming out of the chamber with partial case head separation. Should I have quit using it the first time this happened to a single piece or is ok to run through the rest of of the lot before trashing it? It's been fired 5 times, Nosler brass 280 AI. I am not pushing it that hard and the gun has a tight chamber.

View attachment 244632GREATGOBSOFGOOSE****!!

Uuuh, you aren't REALLY planning to "get one more load" out of those cases, ARE you?!? I hope they are just indicative of what you are seeing in a few cases and you are asking if you should condemn the whole lot of them to err on the side of caution.
PLEASE tell me that's what is happening.
Otherwise, Take Care and be Safe out there.

 

[marchboom]

I would definitely stop using that batch of brass...immediately!. Don't take the chance of having the body of the case stuck in the chamber.

I recently stopped using the same lot of 22-250 brass for the same reason. I now use the "do not use" cases to experiment with sizing dies & mandrels and adjusting the torches on my annealing machine.

Use the paper clip method of detecting a separation and find a case that you can cut lengthwise. This way you can definitely see how close the case is to separating.

 

[diddlyv]

with my M1A back in my high power days 4 loadings was pretty normal before signs of incipient head separation. If lucky got 5 loadings out of GI brass. Had to trim every time as I was making the die contact shell holder every time I sized. Brass did not last long but rifle functioned flawlessly with std dies

 

[StumpGrinder]

Is there a way that my sizing die could be to blame for this?

Are you annealing your brass? Maybe the neck and shoulders are work hardened and pulling on softer brass further down the case. I haven't yet gotten into annealing but with ammo shortage I'll need to make my brass last. I think most competitive shooters anneal every time, and reuse their brass many times.