Applied ballistics accounts for aerodynamic jump. Hornady uses Axial Form Factor to adjust the calculations to match your real world results. AB uses MV Calculation and DSF. Different methods but both make the adjustments necessary to fine tune the computed results to your rifle's performance. I stick with ways I know work, so MV and DSF is for me, but it doesn’t matter for the average shooter unless you are pushing subsonic. This is the reason Capt up there doesn’t notice any issues, his 7mm mag is still screaming even at 1400. Start shooting in mile(s) range with assorted bullets and loads then this stuff becomes important, including spin. Not at 1000.