I undergo hearing tests regularly at work.Over 25 years of hearing tests has shown no noticeable loss of hearing although I hunt without hearing protection.A member of our fish&game club used to say the same thing until he had a muzzle brake installed on his 300winmag.However one shot while hunting without hearing protection caused his ears to ring for several hours.Subsequent hearing tests over the past several years have shown that he has suffered permanent hearing loss as a result of that single shot.
The point is that MUZZLE BRAKES DRAMATICALLY INCREASE NOISE TO THE SHOOTER.The louder the noise the more likely the chance of hearing loss to the shooter.That is a fact.