5-inch-38-caliber-gun-turret Cutaway drawing of the Mark 12 5″/38 caliber U.S. naval gun. (Source: Naval Ordnance and Gunnery, NAVPERS 16116, Bureau of Naval Personnel, Training Division, May 1944.) http://www.lonesentry.com/blog/5-inch-naval-gun-turret.html
A fine view of the sheer scale and complexity of the big gun turret for a Battleship. In this case, this appears to be a British 15" gun mounting, of the type mounted on R class batlleships, "Queen Elizabeth" class and Renown and Repulse.