When one "tunes" their handloads to barrel vibrations, they're changing the point in the barrel's vertical whip cycle at the muzzle so bullets leave at different angles relative to the line of sight. Adjusting the powder charge weight is the best way as that has the greatest effect on muzzle velocity and barrel time without effecting accuracy for a given bullet seating depth.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master