Back in the day, Jackie was kind enough to give me one of his tuners, before they had any rubber on them. (I still have it.) About that time, Sims had come out with their Deresesonator sized for sporter weight (hunting) barrels. I called and suggest that they might want to make one for larger barrels, they did, and sent me a couple. I did with and without barrel ring test on my LV rifle. The difference was extreme. Going down the barrel, tapping with a loosely held very small combination wrench, the sounds were ting, ting, ting. With the Deresonator they were tunk, tunk, tunk. I believe that there are three reasons that these are not seeing much use. They are cheap. They are ugly, and no prominent shooter is using one. With Jackie's tuner, and the Deresonator, my just about worn out, middle of the pack at best barrel shot better than it ever had at a match, winning the last match, at 200, before being retired to fire forming duty. Before the match, i had tested the tuner alone, Tuner with Deresonator on the tuner, and tuner just behind the two inches of threads for the tuner. On the barrel seemed to work best. Back then I had not seen a single tuner with rubber on it.