The HML-4, or Homing Missle Launcher - Mark IV, is a weapons manufactured by Keats' Firearms in 2039.
This version was made simply as an update to the 2038 version.
The HML-4 fires a missle that homes in on the nearest mammal in front of it. It fires three times before having to reload. It's maximum ammo capacity is 27. It is one of the worst weapons to get in Nazi Zombies, as if the zombie(s) you're shooting at is too close you will blow yourself up.