its probably a marketing thing just like the "zmax" ammo is. none of that (zmax) is new load technology (or bullet technology), its just snazzy packaging and a green tip on the same bullet. hornady has confirmed multiple times that product (the zmax) correspond with the equivalent bullet (if its a reloading component) or the equivalent ammo in the standard red tip version. ie: hornady zmax 168gr 308 = hornady amax match 168gr 308.
if i had to guess, this black is likely along the same lines.