While the USAF AC-130 is an awesome platform for surveillance and fire support for troops on the ground, at about $190mm a pop, the Air Force just can’t afford many of them. The Marines decided to generate a little capability by bolting some existing components onto their new KC-130Js, under a program known as Harvest Hawk.

CAMP DWYER, Afghanistan – One of the U.S. military’s most seasoned aircraft has found a new purpose as a one-of- a- kind weapon for the Marine Corps in support of troops on the ground in Afghanistan.
The U.S. military has relied on the C-130 Hercules platform for a variety of tasks including air-to-air refueling, and cargo and troop transportation for more than 50 years. But the Marine Corps, in partnership with Lockheed-Martin, has recently created a unique variant of its KC-130J by outfitting an existing plane with what has been dubbed the Harvest Hawk weapons system.
via DVIDS – News – KC-130J Harvest Hawk: Marine Corps teaches old plane new tricks in Afghanistan.