02-22-2018, 11:23 PM
Unfortunately that's what happens when you suppress an AR. The suppressor keeps pressure in the barrel for longer and when the brass seal is cracked during extraction it all comes back around the case. The spit and crud is coming from the chamber not the gas system and it doesn't matter what gas system or setting you use, the back pressure from the chamber will always be there. The good news is that a coating of carbon on the top rounds in the magazine is cosmetic only. it doesn't affect accuracy. If you hand-load then unfortunately the dirtier cases means extra cleaning, but that's one of the costs of suppression.
What position on the clock face are your spent cases being ejected?
What position on the clock face are your spent cases being ejected?