We’ve written about gunships a few times, most prominently here.
We’ve also written about the Bofors 40mm gun. The only Bofors 40mm/60 guns currently in US service are aboard AC-130s. They’re old, hard to maintain, and ammo for them is becoming hard to sustain.
So the Air Force looked to replace the 40mm with a 25mm gun similar to the gun used on Marine AV-8B Harriers. While that worked, it was very maintenance intensive. So the Air Force next tried to use the Mk44 30mm Bushmaster cannon that was supposed to be the main armament of the Marines Expeditionary Fighting Vehicle. But as it turned out, that gun had poor accuracy when mounted on the AC-130. So the 30mm’s were pulled and replaced with earlier guns, either 40mm or 25mm.
Mostly, this post is an excuse to link some AC-130 video.