I use muzzle brakes by Vais, Pac-Nor, and Mag-na-Brake by Mag-na-port - this is not barrel porting but a removable threaded muzzle brake (http://magnaport.com/rifle.html). My next barrel for a Savage Precision Target Action will include a Sharp Shooter Supply muzzle brake.

I use them on every new rifle, even the .223 Remington, to dampen recoil and/or make hits in the field visible, and reduce the accumulative impact of recoil. The .308 and 6.5-284 both benefit from recoil reduction, especially my 6.5-284 that would occasionally hit my spectacles with the scope. I shoot varmint and do a lot of experimenting off the bench at a public gun club range, recoil thrust acceleration can and will cause concussion over time.

The BS about noise is silly, the muzzle brake does not amplify the noise it directs the blast wave outward, the shooter needs to wear hearing protection regardless. I was employed for years at a public firing range, the noise of all firing must be attenuated by wearing ear plugs at the minimum, and ear plugs and muffs on any firing line. That particular range had a peaked roof over the firing line, it focused the sound pressure waves so that occasionally it would lift my ear muffs enough to make my ears ring, even though I wore plugs under them. When hunting in open country I wear foam ear plugs. If your ears ring when you shoot, you have damaged your hearing. When the ringing stops those nerve cells are gone. Exposure to noise even with the plugs and muffs, and years of doing steel fabrication, left me with a severe hearing loss. When tested, I discovered that even the sizzling noise of a MIG welding torch with carbon dioxide flux gas was producing 90 - 94 decibels, lighter helium and mixed gasses were even louder. The action level for noise exposure is 80 decibels if exposure lasts 4 hours or more. my exposure ran to 136 decibels while grinding steel tubing.

So the upshot is that continual exposure to recoil forces will cause bruising and a concussion, and exposure to muzzle blast noise will damage your hearing and can also result in a concussion. Always wear ear plugs and have a pair of muffs nearby for use on crowded firing lines, especially when that guy with the .50BMG rifle sits down next to you and the wave of hot gas passes over you knocking over your coke and blowing your bag of Cheetos off the bench. Muzzle brakes, ear plugs and muffs - all part of the game, unless suppressors are legalized in all 50 states.