I have a Sig 7.62QD on a Sig M400 9.5" 300BO. It is very quiet. I step across the street and shoot it into the marsh and the bullet hitting the water is much louder than the gun. It's more quiet than a nail gun. I'm shooting S&B 200gr subs. I haven't tested it yet using the Hornady 190gr Sub-X. That's going to be my hog extermination round.