5-inch/54-caliber Mark 16 gun
The 5"/54 caliber Mark 16 gun (spoken "five-inch-fifty-four-caliber") was a late World War II–era naval gun mount used by the United States Navy, and later, the Japan Maritime Self-Defense Force. These guns, designed originally for the s and then the abortive CL-154-class cruisers, were to be the replacement for the 5"/38 caliber secondary gun batteries then in widespread use with the US Navy. Design The 5"/54 cal gun turrets were similar to the 5"/38 caliber gun mounts in that they were equally adept in an anti-aircraft role and for damaging smaller ships, but differed in that they weighed more, fired heavier rounds of ammunition, and resulted in faster crew fatigue than the 5"/38 cal. guns. The ammunition storage for the 5"/54 cal. gun was 500 rounds per turret, and the guns could fire at targets nearly away at a 45° angle. At an 85° angle, the guns could hit an aerial target at over . The cancellations of the Montana-class battleships in 1943 and then the CL-154 class cruisers in 1945 pushed back the first use of the 5"/54 cal guns to their installation aboard the US Navy's s. The guns proved adequate for the carrier's air defense, but were