The BL 13.5 inch naval gun Mk I ("67-ton gun") was Britain's first successful large breechloading naval gun. Mks I - IV were all of 30 calibres length and of similar construction and performance.
The BL 13.5 inch naval gun Mk I ("67-ton gun") was Britain's first successful large breechloading naval gun. Mks I - IV were all of 30 calibres length and of similar construction and performance.
The BL 13.5 inch naval gun Mk I ("67-ton gun") was Britain's first successful large breechloading naval gun. Mks I - IV were all of 30 calibres length and of similar construction and performance.