 The Derfflinger @-@ class ships were armed with eight 30 @.@ 5 cm ( 12 in ) SK L / 50 guns in four twin gun turrets , two forward of the main superstructure in a superfiring pair and two to the rear of the ship , in a similar arrangement . The guns were housed in <unk> C / 1912 mounts on the first two ships , and in <unk> C / 1913 mounts on Hindenburg . The turrets were trained with electric <unk> , while the guns were elevated <unk> , up to 13 @.@ 5 degrees . The guns fired 405 @.@ 5 @-@ kilogram ( <unk> lb ) armor @-@ piercing shells at a muzzle velocity of <unk> meters per second ( 2 @,@ 805 ft / s ) . At 13 @.@ 5 degrees , the shells could hit targets out to 18 @,@ 000 m ( 20 @,@ 000 yd ) . The turrets were modified in 1916 to increase the elevation maximum to 16 degrees . This <unk> increased the range to 20 @,@ 400 m ( 22 @,@ 300 yd ) . The ships carried 720 shells , or 90 per gun ; each gun was supplied with 65 armor @-@ piercing ( AP ) shells and 25 semi @-@ AP shells for use against targets with less armor protection . The 30 @.@ 5 cm gun had a rate of fire of between 2 – 3 shells per minute , and was expected to fire 200 shells before replacement was necessary . The guns were also capable of firing 405 @.@ 9 kg ( <unk> @.@ 8 lb ) high explosive shells . The shells were loaded with two <unk> C / 12 propellant charges : a main charge in a brass cartridge that weighed 91 kg ( 201 lb ) and a fore charge in a silk bag that weighed 34 @.@ 5 kg ( 76 lb ) . The propellant magazines were located underneath the shell rooms for the two forward turrets as well as the rear superfiring turret ; the arrangement was reversed for the rearmost turret . 
