Quote Originally Posted by alamo5000 View Post
One thing that you left out (that I was referring to) wasn't so much the action but rather the port pop of a semi auto. Hot gas trapped in a tube and when you open that up it creates a boom/pop of it's own. On the muzzle all that is blasted out the front, but on a semi auto hot gas is blasted back down the bore of the gun-- and as soon as the action opens it creates a loud pop. This is what makes a lot of guns not hearing safe at the ear, the unsealing of that hot gas at such a close proximity to the shooter's face is noisy aside from just the action.
I knew what you were saying, and agree, port noise is loud, but how loud is the action noise? How much of the loudness is the gas and how much of it is the action moving back and forth? A rhetorical question, but the point is constantly being subjected to noise at a fixed frequency, even if it's "hearing safe" still has the potential to cause damage. I cringe when I'm in a bullet's supersonic cone without muffs because it hurts a little (happens regularly at matches) but I don't cringe at port pop the same way. But I don't want to subject myself to either if I can help it.

But we're in agreement, a can can't really help either substantially.