It isn't a theory, it is a fact. Rimfire competitors, both benchrest and Olympic 3 position, have been using for years. Works on $3.5K rimfires or 350 dollar sporters equally well. Does not matter what the action, how many screws, stock etc.

Want to have some more fun with barrel harmonics? Take 2 orings that will fit tightly on your barrel a few inchs from the end and some small strong magnets. Put the orings just far enough apart to allow the magnets to fit between them then vary the number and position of the magnets with different groups of the same ammo. Works best with a bull barrel of course. Acts just like a rimfire barrel tuner.

http://www.varmintal.com/a22lr.htm