It took a while for the LeverEvolution bullets to hit the streets after the ammo was released, I'm guessing it will take the same for the Z-Max. Being as zombies are fictional characters in movies and this ammo is recommended only for dealing with zombies, it really doesn't matter.
Disclaimer: Hornady® Zombie Max ammunition is NOT a toy (IT IS LIVE AMMUNITION), but is intended only to be used on
ZOMBIES, also known as the living dead, undead, etc. No human being, plant, animal, vegetable or mineral should ever be shot with Hornady® Zombie Max ammunition. Again, we repeat, Hornady® Zombie Max ammunition is for use on ZOMBIES ONLY, and that's not a nickname, phrase or cute way of referring to anybody, place or thing. When we say Zombies, we mean
As UrbanNinja mentioned, it's just the change in polymer tip color from one of their other bullets.