I broke down and put an seeking adjustable gas block on my kids 6 ARC it was way over gassed. One day it shoot fine next day shoot shotgun groups. Get oddball flyers etc. Today it shot very consistent brass ejecting where it’s supposed to eject at 4 etc.
This has been my issue with my ARC build as well. I was just at the range this morning testing it out, and I'm done chasing my tail, I'm ordering an adjustable gas block the weekend we get back home form vacation. I recorded myself shooting and the thing was ejecting brass that would hit the brass deflector and then land about the 1 o'clock area, and destroying brass. I've finally been able to get reloading items for it, but the once fired factory brass is beat to crap.