Wow, that is some interesting information.....

My ears rings for a few seconds after shots, but I can hear and talk. The ringing subsides in less than 30 seconds or so. Same effect as when my buddy cracked off the Ruger M77 30.06. I'm surprised that your friend suffered from just shooting at game, that sounds unusual to me, but I'm not in a position to doubt your word.

I am always careful with hearing protection - I wear it in the parking lot of the range when I get there - it's an outdoor range. The plugs or muffs by themselves have never been enough for me - I have to wear both. I now use the plugs with the electonic muffs - they work pretty well. I even wear this setup while shooting my pistols at qualifications.

I would think that if recoil was not a factor on a rifle, that the CR (conventional recoil) version, which is said to be supplied with all the new BOSS riflesnow, would assist is barrel tuning, without the additional noise.