This is why you don't mix muzzle brake testing with supressor testing
Yeah, we're running our new muzzle brake/comp on an SBR. I got all giddy because I was shooting a triple NFA gun (commando sized supressed select fire) and when I grabbed our test rifle I forgot to don my ear protection.
Commando sized BL + muzzle brake - hearing protection = ouch.
Wasn't as bad as firing a pistol with no ear protection though.
The brake actually does better than birdcage flashhiders on a regular (14.5" Bls and above) sized barrels.