Phil Shoemaker said he tested the Hornady HM .458 Win Mag ammo over his chrono in a side-by-side test with factory .458 Lott Hornady ammo in the same Lott rifle.

Hornady "Heavy Magnum" .458 Win Mag 500gr RN = 2220 fps

Factory Hornady .458 Lott = 2260fps

Fired in the same rifle in a side by side test...