Case Head Separation??

[Rocketvapor]

Heavy load (clickers) is expanding case @ the .2" location.
Pretty normal for hot loads.
Sizing down the web with the ring die so the case fits in your tight chamber is thinning the web.
Material is moved longitudinally, not just compressed radially.
Tight chamber, hot loads, correcting brass expansion with a ring die, case will eventually fail.
Maybe during sizing, maybe not.
Annealing has no impact on lower case body.

Ring die forces material from the zone that sees the most 'work'.
Repeated sizing, bump and trim will take material from body.
Where do you think it came from?

With that much work required to size the case, don't expect 20 reloads from your brass.

 

[JPB4BAMA]

Just in case, good reason to keep a "broken case extractor" in your range bag for EVERY caliber you shoot.
And, you might consider the type of sizing die you use. Full length with the neck button will pull the case longer with every upstroke.
I use bushing bump dies and after 25 to 30 resizes, no case head separations.
Shooting my M1A WILL show you thinning cases.

Any idea where I can find one of these tools for a 284 Win?

 

[Chilly807]

Any idea where I can find one of these tools for a 284 Win?

You might be able to use a bronze brush that's a tight fit in the 284 case neck. The rear half of the broken case comes out on the extractor, the front half stays in the chamber.
You push the bronze brush in from the breech end until the bristles are in the neck, then gently pull it back. Often the broken case comes with it.
If you're unlucky, it won't work.

I'd try a larger brush, maybe one for a 30 cal?

 

[Monte F]

I just use a .45 brush for cleaning pistols that has the twisted wire handle. Shove into case and pull back out. Only had to use a couple of times on cases I missed the thin line starting above the web. Keep it in my range bag so it is always close by when needed.

 

[Rocketvapor]

Had an almost complete separation yesterday.
22 Nosler, Dogtown brass, shot a "few?" times.
I've had a couple split necks but this was a first.

 

[big5ifty]

Just in case, good reason to keep a "broken case extractor" in your range bag for EVERY caliber you shoot.

I was at a match where the shooter cycled the bolt on his 338 LM and the case rim and head is all that came out.

He went off to find something to remove the case, but came back with a piece of wire. So I asked him if I could try with my extraction tool first, and he said sure.

I fitted a cleaning rod with a brass jag, wrapped tight in a strip of material. Inserted from the chamber end till the jag passed the case mouth, then a gentle pull, and it came out.

He asked me where I bought the tool from so he could go get one. I gave him the jag.