Do you still use the mini gun?

Answer 1

The M134 "Minigun" is still in active use, pretty much exclusively on vehicle mounted applications. If you've seen on mounted on a regular tripod, you were probably looking at photos from the Knob Creek machine gun shoot - the minigun is far too impractical to fulfill such a role in any military force.

A limited number are available on the civilian market. To purchase one as a civilian, you must first find one which is for sale (expect to spend upwards of $200,000). You need to get approved for an NFA Class III tax stamp, as well. If you wish to buy one made after 1986, you have to be an FFL licenced dealer with the Class 2 Special Occupational Tax stamp, and have a letterhead from a law enforcement agency allowing you to purchase it as a dealer sample.