6 inch 35 caliber naval gun 1877 was a 152 mm naval gun used by Russian Empire. The gun was used from 1887 as battleship secondary armament and cruiser armament. The gun was mostly replaced by newer 6 inch 45 caliber Canet gun 1892 by Russo-Japanese War, but was still used on some ships. During the First World War fourteen guns were used as a coastal guns on Gulf of Finland in the Peter the Great's Naval Fortress and were taken over by Finland after Finland's Declaration of Independence in 1917. The guns were used by Finland in the Second World War. Russian model year 1877 refers to rifling system, not gun adoption[citation needed].