The BL 12 inch naval gun Mk I was Britain's first attempt to match the large breech-loading naval guns being installed in rival European navies, particularly France. Mks I - VII all had a barrel of approximately 303 inches in length (25.25 calibres) and similar performance.
The BL 12 inch naval gun Mk I was Britain's first attempt to match the large breech-loading naval guns being installed in rival European navies, particularly France. Mks I - VII all had a barrel of approximately 303 inches in length (25.25 calibres) and similar performance.