The most common calibre for the main armament was s, although some ships used smaller guns because they could attain higher rates of fire; British battleships from the Majestic class onwards carried this calibre, as did French ships from the Charlemagne class (laid down in 1894).
Some of the pre-dreadnoughts carried an "intermediate" battery, typically of 8-inch (203 mm) to 10-inch calibre.