Thanks for all the information. She currently runs plugs and muffs with supersonic rifle. I don't want her to hear a permanent buzz like I do(non-firearm related injury). I see the disadvantage of 300 sub ammo but hope it would be outweighed by safer sound levels. I always worry she might not realize her plugs are sealed well. If that were to happen I would hope it would result in non permanent discomfort. She likes my ar pistol w 10.5 barrel. It's not too bad at all with plugs if sealed well. If not sealed well you know it. That's why I make her wear the muffs. I would like to build her an upper or whole rifle of her own so she can set it up to fit her. I don't want to add a new cartridge to the collection but if it will potentially save her hearing I will. I guess it's not that expensive to try out. Just wanted some real world feedback before I waste the time.