Back when the Deresonators were first introduced, they only came with a 5/8" ID for sporter barrels. Being somewhat interested in trying one on my 6PPC, I called them and suggested that they make one that had a bigger hole, for heavier barrels. I was writing benchrest equipment articles at the time, for Shooters News, which had the contract to publish the NBRSA's match results. That was when they started making the one that we use for heavier barrels. They sent me two of the first ones to play with. About that time, Jackie Schmidt, who had done a lot of posting about his tuner experiences on the internet gave me one of his tuners, which at the time did not have any rubber on them and were lighter than the ones that he currently uses. They were three and a fraction ounces. The week before a benchrest match at Visalia, a friend fitted the tuner to a barrel that I had been shooting that was about worn out, and cut steps in the barrel, per my directions, to remove the weight needed to compensate for the added weight of the tuner and Deresonator. I installed the barrel, and went to the range with tuner and Deresonator in hand to do some testing. What I found, after testing with and without, in various configurations, was that my barrel "liked" to have the deresonator two inches back of the muzzle, a the edge of the tuner threads, and the tuner about two turns forward from that. With that combination the barrel shot better than it ever had before, and won the last match at 200 on Sunday with a .295. It had required less fiddling with the load, and shots seemed to be more consistent with what the wind flags had shown, throughout the weekend. After that, if I had had a lathe, I would have cut threads on all of my barrels, and turned steps in them as well. The difference was that dramatic.
Friends have tried Deresonators on their varmint rifles. Some have seen improvement and others have not. My theory is that this is because some may not need what they do. One thing is for sure, if you compare barrel ring with and without, there is a major difference. It goes from a ting to a thud.
IMO the main reasons that more shooters do not use Deresenators are that they are ugly, uncommon, and cheap. No matter what they say, most shooters do not want to look like they are eccentric, and there are lots of people who favor looks to the extent that they would not use something that made their rig look ugly, and of course there are a lot of people who would never believe that something that cheap could possibly work. The last reason is that they know someone who tried one, on one rifle, who did not see any improvement.
The information about the sheet material, further up in this thread is priceless, as is Joe Salt's informaton. Thanks
Boyd