A company by the name of Hornady makes ( drum roll please ), Zombie ammo. Now how this would be different from any other ammo I don't know. It's my belief that any old bullet to the head will put down a zombie. But then again who am I to try and stop good old American capitalism even during a zombie apocalypse.
Hornady's web site reads:
Be PREPARED – supply yourself for the Zombie Apocalypse with Zombie Max™ ammunition from Hornady®! Loaded with PROVEN Z-Max™ bullets... yes PROVEN Z-Max™ bullets (have you seen a Zombie?). Make sure your "bug out bag" is ready with nothing but the best!
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…ZOMBIES!
Each box of zombie ammo contains:
9MM Luger 115 gr. (25-count box)
40 S&W 165 gr. (20-count box)
45 Auto 185 gr.(20-count box)
223 Rem. 55 gr.(20-count box)
7.62×39 123 gr. (20-count box)
308 Win 168 gr. (20-count box)
12 Gauge 00 Buck Shot (10-count box)
Find out more about "zombie ammo" here Hornady.com