Yes. At least the ones on the track-mounted M163 could.
Can an operator take manual control of the Phalanx and use it against ground forces?
The Navy may have some differing engagement rules, but I'm sure they could find a Marine or two around to figure out such a neat use for the thing.
It’d be a primo prize if the jihadis could capture it or destroy it, as unlikely as that would seem to be.
Even better: think of indirect fire, fired at an angle up into the air at a 30º-45º angle upwards, since what goes up must come back down...and the mix of 20mm rounds will almost certainly incluse some nice high explosive rounds among the novelties.
During the Korean and Vietnam Wars, this was sometimes done with the quad-gun .50 caliber mount on deuce-and-a-half trucks and leftover WWII halftracks, and was known as *H&I fire* for Harassing and Interdiction, nicely useful around the mountain passes and bridge choke points of that theatre. Using three ground-mount guns gives a nice effect of around 35 shots per second, with 250 rounds per gun, 400 each if some 5-gallon cans are modified into lkarger .50 ammo cans. If the faster M3 aircraft guns are used, the rate's more like 60-90 shots per second, about a six-second burst before the guns run empty.
Being as the guns are miles away from the impact zone, the first warning the recipients get are the whistle through the air of hundreds of incoming .50 rounds and, perhaps, the first impacts into the ground or nearby targets until one falls somewhere between the ears of the recipient. Taking cover in vehicles does not help a bit, and the infantryman's usual habit of falling prone on the ground is counterproductive in this case.
The Navy Vulcan CWIS used in such a role could offer very nice H&I fire of the sort, indeed, harassing and interdicting the mujis into little pieces not much bigger than your hand. The WWII and Korean vets who fired and saw such missions with the Quad Fifties called them *meatgrinders.* And, as you say, they're handy for direct fire, too.
