I posted a couple of weeks ago with an ejection problem.  But now I have a little more info on what is happening afer my range trip today.

Every 10 rounds or so my AR has an extract/eject problem.  It is always one of 2 situations.  These 2 problems have happened with 3 brands of ammo, and with both Thermold and USGI mags.  I have also tried 2 bolt carrier groups.

Problems:
#1 The ejector breaks a piece of the rim off and the case is stuck in the chamber.  A light tap with a cleaning rod down the barrel removes the case.

#2 SEE PICTURE.  A case is stuck in the ejection port with case mouth pointing outward, and at the same time a new cartridge is feed most of the way into the chamber. If you look at the pic you will see the fired case and a the next cartridge behind it almost chambered (But of course the fired case keeps the bolt from closing).

Could I have a rough chamber?  How does one fix this?

Could it be that I am firing 5.56 and have not tried .223?

Also, it is a used upper.

I appreciate any help.

Sounds like a rough chamber... bust out the dremel and flitz!

i have a dremel, but how is the best way to get up in the chamber?  what kind of bit to use?

Yes, it does sound like a rough/bad chamber. What brand of barrel is it? Just out of curiosity, have you ever checked headspace?

no barrel brand visible.

No, I have not checked headspace.  Would a spent case give me an idea of bad headspacing?