Just as an FYI.
My RRA AR eats everything I feed it except the Radway Green I have in abundance.
In my case, after a magazine or two a case gets stuck in the chamber and I have to pound it out with a cleaning rod.
RRA has .223 wylde chambers so I'm going with a tight chamber and something to do with the brass.
The extractor rips a perfectly extractor sized chunk off the rim of the brass.
Disappointing but the thing literally goes all afternoon shooting Lake City surplus so I'm going with it being mostly an ammo spec issue combined with a .223 chamber.
Just another data point.