I have one that I have yet to fire. To little time I guess. The harmonic dampener does adjust and may or may not make a difference. I'm sure there will be a lot of trial and error as to adjustments and ammo types. Just pick out an ammo to start with, establish a baseline and make your adjustments from there. I'm looking foreward to tinkering with mine. I still have my ranch and tactical Mini-14's that I will not part with so I am hoping that, ammo I am happy with shooting in them, will be even more accurate in the target model. Time will tell.
Enjoy your new rifle.