Weird case/head separation just sent to me

[Intercooler]

     It seems to most I am the only one that shoots 10mm at the range  I have found some brass on 10mm hill though, so someone else does! Anyway... someone sent me this thinking maybe I would know something:

Hey, I found this at the range and thought you might be interested to see it. Fortunately, it did not come from my Delta Elite. The rim does not have any extractor gouges, so it looks like it separated upon firing rather than being yanked apart. I wonder what happened to the firearm. I'll have to ask around at my range and see if anyone had a 10mm handgun blow up.



-Ken

Winchester brass and possible reload?

[The_Shadow]

Judging from the primer not being flattened out it was not a true overpressure event...

Multiple loadings and firings and extractions can hammer and pull at the case head, by that I mean as the cartridge is fired, it expands tightly to the chamber walls, the pressure further builds pushing in all directions, including rearward.  This constant stretching, pushing of the case can cause a flexing or work hardening of the entire casing.  This can lead to micro fracturing of the alloy casing structure, lack of support at the rear of the casing also allows more stretching and increased fracturing.

What if this case was lightly smiled, resized without notice, reloaded to upper levels working it further till it fails.

Some handloaders are using wet cleaning of their cases, if they use any chemicals known to attack the brass alloy (ammonia in particular), it can cause issues on a molecular level.

In short, nothing last forever...Maybe you will find the person or hear of the story about what happened!

[DenStinett]

The break looks very clean, other than it looks like the Brass has crystallized
Maybe it was exposed to Ammonia or some other chemical ?
Or fired while under severe (and I mean SEVERE) cold ?

[Geeman]

Maybe a stuck bullet?

Looks kinda clean for a case separation in a traditional event.  hope the guy is ok.

Greg