The main armament for all of the "Six-Six Fleet" armored cruisers was four Armstrong Whitworth-built 45-caliber eight-inch guns in twin-gun turrets fore and aft of the superstructure. The electrically operated turrets were capable of 130° rotation left and right, and the guns could be elevated to +30° and depressed to −5°. The turret accommodated 65 shells, but could only be reloaded through doors in the turret floor and the ship's deck that allowed the electric winch in the turret to hoist shells up from the shell room deep in the hull. The ship carried a total of 320 eight-inch shells. The guns were manually loaded and had a rate of fire about 1.2 rounds per minute. The 203-millimeter gun fired armor-piercing (AP) projectiles at a muzzle velocity of to a range of .