yeah the gun was designed for special ammo, but it proved to costly to buy in any quantity. so there is none. there are articles on this aluminum death trap on the drive-the war zone.
When the USS Belknap collided with the USS JFK a few months before I came aboard, the plane captain training me told me how they could see streams of molten aluminum from the superstructure running down the side of the hull hissing steam as they entered the water.
I wonder how they have changed (if they changed) after that.