15 cm SK C / 28 The 15 cm SK C / 28 was a German , medium - caliber , naval gun used during the Second World War . It served as the secondary armament for the and s , s and the s . A number of surplus weapons were used as coast - defense guns and eight were adapted to use Army carriages and used as heavy field guns as the 15 cm Schiffskanone C / 28 in Mörserlafette Description . This gun was designed as a smaller and lighter version of the 15 cm SK C / 25 guns used as the main armament of the - and s . It shared the earlier gun ' s design with a loose barrel , jacket and breech - piece with a vertical sliding breech block . Naval mountings . The " Drh . LC / 34 " twin - gun mount was the most common mount for the gun in the Kriegsmarine . It was used as the secondary armament of the and s and was planned to equip the proposed H - class battleship s . The mount weighed between , depending on its armor thickness ; the Scharnhorst ' s mounts had between of armor while the Bismarck ' s had . Maximum elevation was 40° , giving a range of and maximum depression was - 10° , while maximum elevating speed was 8° per second . Each mount was designed for full 360° of traverse , but was limited to much less than that by the ship ' s superstructure . Speed in train was a maximum of 9° per second . The fastest firing cycle was 7 . 5 seconds , or 8 rounds per minute . Ammunition was supplied by twin hoists between the guns , at the rear of the mount . The was intended to use a lighter version of this mount with thinner armor that only weighed approximately . This may have designated as the " Drh . LC / 40 " , but development ceased when the ships were canceled in 1939 . The s were going to carry eight twin - gun " Dopp MPL C / 36 " casemate mountings . These weighed and had an armored shield thick . The mount elevated at a speed of 6° per second and trained at a rate of 8° per second . Coast defense mountings . The " Küsten - Marinepivotlafette ( Küst . MPL C / 36 ) " was a highly successful mobile coast defense mount fitted with a gun shield . The gun traversed on a six - legged firing platform that allowed 360° of traverse . It could depress - 7° and elevate to a maximum of 47° 30 ' , which gave it a range of . The gun on its carriage weighed . It was towed via two two - axle trailers , one at each end . For travel the four lateral legs of the platform folded vertically . It entered service in 1940 . Army mount . Production of carriages for the " 21 cm Mörser 18 " and the " 17 cm Kanone 18 in Mörserlafette " exceeded the available number of barrels in 1941 and eight " SK C / 28 " barrels were adapted for use on the carriages as the 15 cm Schiffskanone C / 28 in Mörserlafette . They were converted to Heer - standard percussion firing . Most guns were replaced by barrels as they became available , but one battery retained them through the beginning of the Battle of Kursk in July 1943 . Ammunition . The " SK C / 28 " used several different shells depending on its target . The " 15 cm Sprgr L / 4 . 6 KZ m Hb " weighed and had a muzzle velocity of . It was a nose - fused HE shell with ballistic cap with two copper driving band and a lead ring behind them to act as a decoppering device by scraping away any copper residue from the driving band . The " 15 cm Sprgr L / 4 . 5 Bd Z m . Hb " was a base - fused shell with a ballistic cap and weighed . It was roughly equivalent to the British " Common Pointed " and also used a lead decoppering ring . The armor - piercing " 15 cm Pzgr L / 3 . 8 m Hb " shell had a ballistic cap and weighed . All shells used of propellant in an artificial silk bag , housed in a brass cartridge case . An illumination shell was also available , although details are unknown . History . Surplus naval mountings were used to reinforce German coast defenses from Norway to the French Atlantic coast . These included guns from incomplete or disarmed ships like the aircraft carrier or the battleship . For example , three or four of the " Graf Zeppelin " s " Dopp MPL C / 36 " mounts equipped both batteries of " Naval Artillery Battalion ( Marine - Artillerie - Abteilung ) 517 " at Cap Romanov near Petsamo , Finland while two of the " Gneisenau " s " Drh . LC / 34 " mounts were emplaced on the west coast of Denmark at Esbjerg where they equipped " Batterie Gneisenau " of " Naval Artillery Battalion 518 " . All told , a total of 111 " SK C / 28 " guns were employed on coast defense duties in a variety of mounts , 28 in Norway , 12 in Denmark , 24 in the German Bight , 8 in the Netherlands , and 39 in Belgium and the Atlantic coast of France . Surviving guns in Norway and Denmark were used throughout the Cold War by both countries .