Oerlikon, now a subsidiary of Rheinmetall, builds a self contained, quick firing, 35mm quick firing revolver cannon for shipboard and land base defense. It is a different concept than the standard Phalanx gun used by Allied navies. The 4 chamber revolving belt-fed cannon is more akin to a giant automatic shotgun, than a Gatling gun.
Rheinmetall press picture of Millennium Gun
To be sure, hitting missiles that are homing in on your ship is a daunting task. In order to have time to track, identify and hit something that looks like a baseball bat flying 3000 mph you almost have to give up human control, and artificial intelligence is being prepped for the task. Oerlikon, however, has been building anti-aircraft guns for quite a long time, and their solution is a bit different.
Ahead round's prefragmented payload
The heart of the gun is it's ammunition. The Millennium can fire many different types of ammunition, in order to counter any number of threats, but the Ahead round is the most interesting. Not only can it counter ship killing missiles, but is also effective against land attacks by rocket, artillery or mortar shells. The round is pre-fragmented, and is programmed as it leaves the barrel to separate into 152 spin-stabilized tungsten fragments at the optimum time into the target path of the incoming threat. In less than a second, from 18 to 24 rounds are grouped together forming a metallic cloud that the threat is not likely to survive.
And in the sales pitch, the whole thing is self contained in an easily installed turret. All you need to feed it is electricity to charge it's batteries, a radar input and someone to say "fire!", and you are ready to go.
The following video is the Millennium Gun in action with the Royal Danish Navy, from the FirstSeaLord01's channel