槍口初速
The ships' primary armament consisted of two 21 cm SK L/40 C/97 built-up guns in single gun turrets, one forward and one aft. The turrets were C/97 type mounts, which were hydraulically operated and hand-loaded. The turrets had a range of elevation from -5 to 30 degrees, and at maximum elevation, they had a range of . Muzzle velocity was . The guns were supplied with 58 rounds of ammunition each; these were shells.