 The Admiral @-@ class ships mounted eight BL 15 @-@ inch Mk I guns in four twin hydraulically powered Mark II turrets , designated ' A ' , ' B ' , ' X ' and ' Y ' from front to rear . The guns could be depressed to − 3 ° and elevated to 30 ° ; they could be loaded at any angle up to 20 ° , although loading at high angles tended to slow the gun 's return to battery . The ships carried 120 shells per gun . They fired 1 @,@ 920 @-@ pound ( 871 kg ) projectiles at a muzzle velocity of 2 @,@ 467 ft / s ( 752 m / s ) ; this provided a maximum range of 29 @,@ 000 yd ( 26 @,@ 518 m ) with armour @-@ piercing ( AP ) shells . 
