The secondary armament consisted of sixteen guns in eight twin mounts, weighing 81 tons each. They were grouped at the four corners of the citadel, with a twin mount on the main deck and another superimposed above it nearer amidships. This disposition gave better arcs of fire, freedom from blast, more separation of the magazines and a better arrangement of the ammunition supply. The cupolas for these mounts revolved on either the upper or superstructure deck; between deck mountings travelled on roller paths on the armoured deck. This permitted a flat-trajectory or high-angle fire. Loading was semi-automatic, normal rate of fire was ten to twelve rounds per minute. The maximum range of the Mk I guns was at a 45-degree elevation, the anti-aircraft ceiling was . The guns could be elevated to 70 degrees and depressed to 5 degrees. However, the guns could only practically fire seven to eight rounds per minute, due to the heavy weight of the shell and the fact that the 5.25-inch round was semi-fixed, requiring the crew to separately load the cartridge and shell into the breech. "King George V" introduced the High Angle Control System Mark IVGB anti-aircraft fire control system to the Royal Navy, which, along with the Mk IV Pom-Pom Director, pioneered the use of the Gyro Rate Unit.