You reckon this applies, even with the Stellite baffles of the Sandman? Similar to OP (but with 5.56), I'm looking to add the Sandman to a 10.5" 5.56 rifle and was thinking flash suppressor, simply because the SiCo 3 chamber ASR brake it's got on it now is tooth-rattling loud when firing unsuppressed.
FWIW, I do see some erosion on the first baffle of the brake (probably 5k rounds through it), but it's made of stainless steel rather than Stellite. Not what I would consider an alarming amount, but I'd be curious if there'd be any erosion at all if the brake/baffle were Stellite...