Major Dave, my rifle is a 223 bolt gun. I suppose it's the least noisy rifle I have, but still is loud. I was doing Ok till the carport incident during my severe attack of stupid.
As for the guy next to you at the range, I went to the range one morning in Houston (where I used to live) and set up on the 200 yard line. The guy next to me was setting up to shoot, but I wasn't paying much attention till he cranked off a round. It was a 460 Weatherby with muzzle break. I think when he did that, all the stuff on my bench was blown 6 inches to the left. I went and had coffee, knowing that he wouldn't be shooting that thing all morning. I'm sure that rifle was brutal to him and to me, all at the same time.
As for the suppressor, my cousin has one on a rifle. I'll just ask him what reduction in noise level he's seeing. He won't be shooting subsonic ammo, so will have info that would apply to my situation.