Machine Head

 is a challenge perk in Fallout: New Vegas. It is gained after killing 50 robots.

Effects
Bonus damage to robots (Mister Gutsy, Robobrain, Protectron, etc...). This perk stacks with other bonus damage perks such as Lord Death and Robotics Expert.

Bugs

 * Although there are 3 ranks for this perk, a bug in the reward script makes it impossible to get the third rank. The same bug also causes the notification to misreport the rank that is given. When rank 1 is given, the notification says that you've been given rank 2, and when rank 2 is given, the notification says that you've been given rank 3.
 * This bug appears to be fixed with the latest patch, however it only has two ranks.