A very good friend of mine recently took the AR plunge. He purchased a Colt LE6920, from an online dealer. He received the rifle yesterday, and though that it looked like there were burrs on the inside. He sent me these pictures, based on my limited knowledge It doesn’t look right to me either. Any help from you veteran’s would be appreciated.
Looks like it could be carbon build up. But not sure. Does it wipe away? Was the rifle new or used?
He bought it new. And he just confirmed it does not wipe away.
I would get in touch with Colt then since it looks like a defect of some sort.
I could be wrong, but I thought I read that Colt has been using that grey Teflon coating on the interior of their uppers for a while now…Kind of like LMT.
If that’s the case, then it looks to me like that Teflon finish was unevenly applied, but I wouldn’t be very concerned as that finish wears off rather quickly anyway, exposing the black anodizing underneath…which is what you might be seeing here.
It’s called dry film lubricant.
Great info as well. His FFL told him that it was a 2013 model that they shipped.
2013 model or 2013 config (magpul buis and pmag) ?
Im not sure what you are referencing. Burrs? If you are talking about the grey substance that is coating the interior of the upper, its definitely dry film lube and its definitely supposed to be in there (per milspec). Is there something else that you’ve noticed?
This coating had been on the inside of these receivers since 1959
After a few range sessions, it’ll be a distant memory.
I believe both.
Normal, just dry film lube.
As it was once put to me, Colt builds war horses, not show ponies…
He was worried about burrs on the barrel to the left of the feed ramps.
There isn’t a thing wrong with that. Tell him to go shoot his gun.
I can understand getting a new gun and wanting it to be absolutely perfect but…
I’m sure the aforepictured gentleman doesn’t lose sleep over his rifle.
Ok ok…I’ve only owned one Colt, so I’m a little behind on my info 
I didn’t see any burrs in the pictures, is it possible to get better pics?
I think he meens around the feed ramps,or at the top of the feed ramps in picture 1… you can see if you look close,looks like machine marks, shouldnt hurt a thing, also as stated the grey stuff is dry film lube.