The BL 15-inch Mark I succeeded the BL 13.5-inch Mk V naval gun. It was the first British 15-inch (380 mm) gun design and the most widely used and longest...

The BL 18-inch Mk I naval gun was a breech-loading naval rifle used by the Royal Navy during World War I. It was the largest and heaviest gun ever used...

The BL 6-inch gun Mark VII (and the related Mk VIII) was a British naval gun dating from 1899, which was mounted on a heavy travelling carriage in 1915...

British BL 8-inch howitzer. Mk I used barrels from BLC guns Mk I/IV; Mk II & III used barrels from BL Mk IV or VI; Mk IV used BLC Mk I/VI adapted for Mk IV...

The BL 13.5 inch Mk V gun was a British heavy naval gun, introduced in 1912 as the main armament for the new super-dreadnought battleships of the Orion...

British BL 6-inch gun Mk XIX was introduced in 1916 as a lighter and longer-range field gun replacement for the obsolescent BL 6-inch gun Mk VII. The...

The BL 6-inch Mark XII naval gun was a British 45 calibre naval gun which was mounted as primary armament on light cruisers and secondary armament on...

The BL 12 inch Gun Mark X was a British 45-calibre naval gun which was mounted as primary armament on battleships and battlecruisers from 1906. It first...

The QF 4 inch Mk V gun was a Royal Navy gun of World War I which was adapted on HA (i.e. high-angle) mountings to the heavy anti-aircraft role both at...

The BL 4-inch Mk IX naval gun was a British medium-velocity naval gun introduced in 1917 as secondary armament on the Renown-class battlecruisers and Glorious-class...

in the British Royal Navy, where it was designated BL 14-inch gun Mk II. The design of the 14-inch/45-caliber dates to about 1910. They entered service...

The BL 9.2-inch Mk IX and Mk X guns were British breech loading 9.2-inch (234 mm) guns of 46.7 calibre, in service from 1899 to the 1950s as naval and...

The Breech Loading 5.5-inch Mk I was a naval gun used by the British Royal Navy during both World Wars. This weapon was developed by Coventry Ordnance...

The BL 4-inch gun Mk VII was a British high-velocity naval gun introduced in 1908 as an anti-torpedo boat gun in large ships, and in the main armament...

The BL 14-inch Mk VII naval gun was a breech loading (BL) gun designed for the battleships of the Royal Navy in the late 1930s. This gun armed the King...

The BL 9.2-inch Mk I–VII guns were a family of early British heavy breechloading naval and coast defence guns in service from 1881 to the end of World...

The BL 5-inch guns Mk I – Mk V were early British 5-inch rifled breechloading naval guns after it switched from rifled muzzle-loaders in the late 1870s...

The BL 12-inch Mark VIII naval gun was one of the first large British rifled breech-loading naval guns designed for the higher pressures generated by the...

calibres length. The gun was originally designed to replace the older BL 5-inch (127 mm) naval guns. It was optimised for the modern smokeless propellants...

The BL 13.5 inch naval gun Mk I ("67-ton gun") was Britain's first successful large breechloading naval gun, initially designed in the early 1880s and...

20th century. In British service it was known as the QF 6-inch Mk I, II, III guns. As the 15 cm/40 (6") 41st Year Type naval gun it was used for pre-dreadnought...

The BL 12 inch naval gun Mk I was a British rifled breech-loading naval gun of the early 1880s intended for the largest warships such as battleships and...

The BL 8 inch guns Mark I to Mark VII were the first generations of British rifled breechloaders of medium-heavy calibre. They were initially designed...

The BL 8-inch howitzer Marks VI, VII and VIII (6, 7 and 8) were a series of British artillery siege howitzers on mobile carriages of a new design introduced...

but unrelated to the BL 12-inch railway howitzers Mk I, III and V produced by the Elswick Ordnance Company at the same time. The Mk IV was a more powerful...

The BL 10 inch guns Mks I, II, III, IV were British rifled breechloading 32-calibre naval and coast defence guns in service from 1885. The British 10-inch...

BL 6-inch naval guns were shortened and bored-out to produce BL 8-inch howitzers as follows : 12 BLC guns Mk I/IV became 8-inch howitzer Mk I 6 BL Mk...

siege howitzer. It was similar but unrelated to the 12-inch siege howitzers Mk II and IV. Mk I was introduced from March 1916. It is identified by its...

reverted to 45-calibres guns in new warships from 1914 onwards with the BL 6-inch Mk XII gun. Of the 177 produced 126 remained for Royal Navy use in 1939...

5 inch Howitzer or the QF 4.5 inch AA gun. By the end of the 1930s, the First World War-era (5-inch calibre) BL 60-pounder gun Mk. I of 1905 and Mk. II...