i had the MDT mags for my 6br and they fed fine for me. Ran about 1k through the same mag and had zero hang ups. Would assume their normal SA mags without the BR adapter plate will perform just as well.
ARC mags with LRI follower has worked flawless for me in the matrix, Terminus Zeus action and 6GT. Never had a feeding issue once in 1000 rounds and 7 matches.