Thanks. So far the only issue with the brass getting trapped has been when I had the EoTech mounted. It saddles over the pic rail and closes the opening just enough to grab a casing once in a while. Eliminating that issue with a CASM mount for my EoTech plinker/coyote blaster.
Early on I learned about ARMS18 issues and chose to open up every bolt for a good greasing with Lubriplate on everything, especially the ejector spring. Replaced two extractors with USGI cause they just didn't look right. So far, I have had really good luck with four installs using low and medium rings.
Another thing I do after stripping a side bolt is apply blue Loctite liberally with not so much gorilla torque. The ARMS18 mounts have not loosened up one time.