What Might Cause this Brass Damage?

[10mm-Admirer]

See pics below.  My Kimber Stainless Target II 10mm has torn up a few cases lately.  Can anyone tell me why? The handload is a book load and was assembled with care. The pistol did not jam. Starline case.  No obvious marks on the ejection port area.  Primer looked normal. The pistol has been 100% reliable with anything I've fed it.





Thanks!

[The_Shadow]

Most likely cause is the extractor tension holding and trapping the casing instead of turning it loose...

[fltbed]

It could also be the extractor loosing tension, allowing the case to shift and not get a solid hit on the ejector.
It could also be a broken or damaged ejector.

Jeff

[10mm-Admirer]

I shot some more of the same ammo with the Kimber 10mm afterward and there was no damage to those cases.  I also shot some of the same ammo in my Glock 20SF with KKM barrel with no damage.  So probably not the load? Maybe just a quirk? What do you think the case mouth hit to cause that much damage?

[sqlbullet]

It was smashed between the breech and the barrel hood. If you check them against the barrel hood you will find a really good fit at a certain point.  Ask me how I know.



I had the same issue.  It is almost certainly extractor tension in your Kimber. 

The inconsistencies are partly because it matters some where in the magazine the round was.  Magazine springs behave differently as they move up the stack, moving through bind and unbind.  We all notice this when emptying a mag by hand.  Some places it really spits them out, others it has less energy.  Those places with a bit less energy the next round doesn't smack the spent round quite the same, if the extractor/ejector didn't do their job.  Sometimes the smack gets the spent case clear, sometimes not.

Here are some videos on checking and if needed adjusting extractor tension.

Direct links:

https://www.youtube.com/watch?v=A_ybp51lx6w
https://www.youtube.com/watch?v=UOSmJd7HaDY
https://www.youtube.com/watch?v=dorzFGvYj40

[10mm-Admirer]

sqlbullet - Thank you so much for the great pics and links.  I really appreciate your help and time!