Installed one on my Anschutz 64 Model 1903 last year. I went from a low 1500 score per card to high 1600 scores with at the time on that rifle a high of 1925. But I also started head spacing the ammo I was using too, so that may have helped some. But yes, I have used in it benchrest, more specifically ARA and it has helped. To me it is nothing more then a cheap version of the mid barrel tuner.
It is cheap enough to try on your rifle and see if it does something.
Bill