I own one firearm with a muzzle break, a 358 Norma Mag. Until two seasons ago I had only shot it from a bench with hearing protection.
So two years back, was in the blind with a buddy waiting for a black bear to join the party, which a good one did. I carefully leaned forward to get the barrel out through the tent and squeezed off a 250gr Oryx. Next thing my buddy breaks out like he has tourettes, and I thought, no way did I miss that bear, but that wasn’t it. The blast from the brake was the problem, on his ears and the blind. It ripped and melted some of the screen as well as ripped the shit out of the front corner of the blind fabric. After a few minutes of him cursing me for my choice of rifle we went over and got the bear and all was forgiven.