My buddy runs a can on the end of his Savage Mark II and, when he runs subsonic through it, it's amazingly quiet. You can literally hear the firing pin striking the case and, half a second later, you can hear the bullet going through the target.
If you cannot or do not want to spend the money on a suppressor, you can always purchase a 452 Ultra Lux. This model has such as long barrel that the bullet begins to decelerate before it has left it. This makes for a very quiet shooter.