I thought my 28" 257 Weatherby had reduced muzzle blast until I shot it from a pop up blind. The muzzle was out the window and the blast still destroyed the screen and my ears are ringing almost a week later. No fool like an old fool, the ear plugs were back in the truck.
I am with those that say a longer barrel will help but not enough to shoot without hearing protection. I also think a recessed 11 degree target crown deflects more noise away than a more flat muzzle crown. I think you would have to go to something like a 218 Bee, Hornet or 300 Whisper to reduce noise significantly, but still hearing protection would be needed.
