BL 7.5-inch Mk I naval gun

The BL 7.5-inch gun Mk I was a British 45-calibre, medium-velocity, naval gun which entered service with the Royal Navy in 1905.
History.
This gun was only mounted on "Devonshire" class cruisers commissioned in 1905, and was quickly superseded by the 50-calibre 7.5-inch Mk II gun.