This is really interesting..... I took someone stalking this weekend at home- farm manager complaining bitterly about deer damage again. The chap had a very smart new Sako 85 in .243 with a Hardy gen IV mod. The first shot he fired on the zero range I thought to be very loud for a moderated rifle, after the second I retrieved some ear defenders from the truck. I then had a couple of shots myself to see if it was something to do with where I was standing in relation to the mod. same effect. We then screwed my ASE utra JET -Z compact on and the difference was quite marked, considerably quieter.
I have absolutely no axe to grind with Riflecraft, they have done a couple of excellent bedding jobs for me in the past- but to my ears at least the Hardy mod is particularly loud. I've read what has been said about the mods and the direction in which they vent the muzzle gasses and find this interesting. I can quite believe that this may result in them sounding louder to the shooter where a sound meter placed adjacent to the mod might detect no difference. However I use moderators on my stalking rifles for no other reason than to protect my hearing and for that reason will not be buying a Hardy (despite it being beautifully made and extremely light).