 "Missouri"s main battery consisted of nine /50 cal Mark 7 guns, which could fire armor-piercing shells some .Her secondary battery consisted of twenty /38 cal guns in twin turrets, with a range of about .With the advent of air power and the need to gain and maintain air superiority came a need to protect the growing fleet of allied aircraft carriers; to this end, "Missouri" was fitted with an array of Oerlikon 20 mm and Bofors 40 mm anti-aircraft guns to defend allied carriers from enemy airstrikes.