127-mm Oto Melara Compact naval gun

The Oto Melara 127-mm (5-in)/54-caliber dual-purpose naval gun fires standard U.S. Navy 5-in ammunition, though it is of Italian design and manufacture. The single-barrel, water-cooled gun has a large ready-round storage capability, consisting of three 22-round drums from which it can fire 44 round s before any crew intervention is required.

Each drum can hold a different type of ammunition and the automatic firing system can select any of the three drums at any time. The drums...