Major discoloration on my RRA upper. I have only used light coats of REM oil for cleans, never ever anything else. The weapon is only one year old with about 1000 rnds fired. I have not contacted RRA yet, I wanted to get some insight on what might have caused this. 
Have you tried putting oil on it recently? Looks oxidized.
Looks like primer paint. I dont know I have never had that problem with mine. I would suggest you contacting RRA. If you have an account on taht other site post a pic of it in their industry section. The rep there Steve will help you out.
Rem oil dries out. Try rubbing it down with Militec or Slip2000 oil and see if it then looks normal.
Update: For the past two days I have applied heavy coats of Rem oil and let it soak in. It appears to be back to normal finish. I’ll let it set for a couple days without applying oil to see what happens.
Rem oil would be my last choice.
I have never ever had any luck with it at all
slip 2k
fp-10
I will def switch, honestly, I think the Rem oil was the problem in the first place. Thanks for the input. I will try the others.
Buy some Slip2000 and their cleaner/degreaser to get rid of the RemOil first, then use the Slip2k.
I’ve seen that happen to uppers after they’ve sat in a hard case for a while.
Why are you using REM OIL on a AR? Thought REM OIL was for shot guns. I would use Break Free if SLIP2000 is not available, however Slip2000 is the S@#t.
Have you by any chance packed the rifle in Dessicant like a Salt-Crusted Tuna? 
LOL…no.