One of my co-workers is having a problem with an AR he built. Upon extraction of a spent case, the brass is somehow dented in roughly the middle of the case. His rifle will even sometimes rip the neck off the brass.  Any idea whats causing this? Any ideas on how to remedy the problem?

Thanks

The dents are most likely caused by the brass deflector on the side of the receiver.
I never heard of case necks being torn off before.

Send more information:

Type of rifle
type of ammo
pictures of the damaged neck if you got them

This will aid in determining what the problem is.

It doesn't look anything like this, does it?

(Yeah, I think I fixed the links!)

My AR jammed with this round in the chamber the other day (first jam in quite a while).  I had to tug like crazy to get the round to extract.  At first I thought I was SOL and my day at the range was over... then it popped out.

[img]http://greghavener.com/images/jam1.jpg[/img]

[img]http://greghavener.com/images/jam2.jpg[/img]

Its a model 1 sales upper and 16" 1:9 or 1:8 twist. He has had it on both an Eagle Arms lower and a Bushy lower.  Handloaded, Winchester brass, VVN130 55 or 50 gr BTBT

This is kind of hard to explain, but take a look at the front edge of the brass deflector where it meets the ejection port.  See the sharp edge?  That is most likely your problem.  Try placing a few layers of tape over that to see if it solves the problem (temporarily, anyway).  I've heard of people gluing on rubber strips (or stick on velcro)... for me, a dremel and a flat black touchup pen did the trick.  A lo-pro receiver w/o brass deflector would work on a varmint / bench rifle.

As far as your brass being ripped in two... I sometimes have case separation with COMMERCIAL brass in my FAL (it's thinner).  It has never done this with mil-surplus or my reloads using Lake City brass.

Scot

For starters, he might want to try some commercial ammo and see what happens.

I kinda suspect the ripped off necks might have something to do with his reloaded ammunition.

You never answered my question... does the dent look my brass that I posted?  That brass got dented but the cartridge still got fed into the chamber.  It was too dented to seat fully, but I imagine if it had fired the gun would have an awful hard time ejecting that brass.