Well I brought my new (used) Bushy 11.5/ 5.5" upper out for a test fire today.  The lower is a Bushy w/ collapsable stock that I've had since new.  The bolt and b/c/g are all brand new from Bushmaster.  I put 120 rounds threw it and the thing is a shooter, nice groups.  Upon looking at the spent cases, they all have a small, horizontal (if you were to stand the brass on end) "ding" on them about half way up the case and seemed dirtier than normal.  Also, the brass didn't seem to get launched as far as my other uppers tend to do.  The ammo was WWB 55gr.  

Now I just broke it down for cleaning, and the barrel under the HG is filthy, the buffer, and most of the interior of the upper have a serious excess of fouling.  What's the deal?  Are the rings not seating properly?  

Thanks-
--VT

My brass (Q3131) in my mid-length build has the same ding in the side...I believe Tweak said it was normal. My brass ejects about 2 o'clock and I have a D-Fender, ISMI recoil spring, and H buffer.