German WWI 10.5 cm brass case

Faintly but clearly marked Karth. Over 586, Patronenfabrik Karlsruhe. Dated Jan. 1918, Sp. 255 inspector's mark. With original primer nicely marked. 19 3/4 inch long, 502mm, rimmed case. The 10.5cm naval gun was primarily used on pre war light cruisers and U-boats. When these ships had larger calibre guns installed in late 1916 the naval guns were move onto land for fixed emplacement. This is substantiated by a flaming grenade mark at the 3 o’clock position on the base of the casing that indicates this was originally marine ammunition taken over by the land army. Empty and inert.