Larry, after shooting many thousands of rounds in competition, p. dogs, chucks, and ground squirrels I shoot with the Peltor Tac6 and a pair of ear plugs at the same time. My ears ring, but not enough to be a bother all the time. I do shoot a lot of big boomers with muzzle breaks at this time, so I think that the over kill on ear protection is adequate.
About 10 years ago, I shot a bull elk with a 7 mag with out ear protection with a gun that had a Vias Muzzle break on it...bad news to say the least! I was wearing my pair of Tac 6's, but had stopped to take a wizz, pulled off the muffs, when a big bull elk ran across in front of me. I shot at him three times while I wet myself, finally killing him on the third shot. My ears have rung ever since.
I wear the Tac-6's all the time when I am hunting now,even when I take a wizz, it is great because I probably hear what is going on in the woods 3 times better than the average human with normal hearing!