Hey Folks,
I skimmed through the link and I would say what they're offering mostly likely helps with accuracy, but it's not the be all end all solution. A barrel on any firearm takes the most abuse out of all the parts, tremendous pressure, high heat, a bullet scraping its way through it each time you pull the trigger. A 30-06 springfield cartridge produces avg of 60,000 psi and .223 produces 50,000 psi on avg. The barrel flexes (they use term Harmonics) and then returns to its original shape and position, mostly. Any product that can legitimately reduce or midigate any of those factors (pressure, heat, friction) should improve the gun's consistency & accuracy.
But keep in mind even the most precise technologically advanced firearm is only as accurate as the person shooting it.