 Blücher was equipped with twelve 21 cm ( 8 @.@ 27 in ) SK L / 45 quick @-@ firing guns in six twin turrets , one pair fore and one pair aft , and two pairs in wing turrets on either side of the superstructure . The guns were supplied with a total of 1 @,@ 020 shells , or 85 rounds per gun . Each shell weighed 108 kg ( 238 lb ) , and was 61 cm ( 24 in ) in length . The guns could be depressed to − 5 ° and elevated to 30 ° , providing a maximum range of 19 @,@ 100 m ( 20 @,@ 900 yd ) . Their rate of fire was 4 – 5 rounds per minute . 
