I've gone back to an AR15 in 7.62x39 with my Harvester on it to hunt with. Quieter than the AR's in 308's and not as sharp as the 223's to me. Just know that if you shoot in an open space, it will sound much quieter than in heavy woods due to the sonic crack being reflected back at you. I don't do 300BO so can't really comment on it. I have heard 308 subsonic rounds out of my bolt gun and they are stupid quiet; but not making much power either. If you are using AR platforms, adjustable gas blocks will be your new best friend.
