From what I understand, regular folk can't automate firearm actuation. Off he top of my head, you would at least need a Type 7 license with a class 2 SOT from our friends at the ATF to automate weapon fire on a drone.
The FAA other alphabet soup agencies probably have other regulations regarding the manufacture and use of a flying killing machine.
The FAA other alphabet soup agencies probably have other regulations regarding the manufacture and use of a flying killing machine.
Some info on ATF licenses: http://en.wikipedia.org/wiki/Federal_Firearms_License