 The Lion @-@ class ships mounted eight BL 13 @.@ 5 @-@ inch Mark V guns in four twin hydraulically powered turrets , designated ' A ' , ' B ' , ' Q ' and ' Y ' . Unlike the two previous classes of battlecruiser in the Royal Navy , which had turrets fore , aft and on each wing of the ship , the Lion class ships had their main armament mounted in a single line from front to rear , with ' B ' turret superimposed over ' A ' turret , ' Q ' turret mounted amidships , and ' Y ' turret aft . The guns could be depressed to − 3 ° and elevated to + 20 ° , although the rangefinders controlling the turrets were limited to + 15 ° 21 ' until superelevating prisms were installed before the Battle of Jutland in May 1916 to allow full elevation . They fired 1 @,@ 250 @-@ pound ( 567 kg ) projectiles at a muzzle velocity of 2 @,@ 582 ft / s ( 787 m / s ) ; at 14 @.@ 75 ° , this provided a maximum range of 20 @,@ 000 yd ( 18 @,@ 288 m ) with armour @-@ piercing ( AP ) shells . At 20 ° elevation , the range was extended to 23 @,@ 820 yd ( 21 @,@ 781 m ) . The rate of fire of these guns was 1 @.@ 5 – 2 rounds per minute . The ships carried a total of 880 rounds during wartime for 110 shells per gun . 
