The BL 16-inch Mark I was a British naval gun introduced in the 1920s and used on the two Nelson-class battleships. A breech-loading gun, the barrel was 45 calibres long meaning 45 times the 16-inch (406 mm) bore – 60 ft (18 m) long.
The QF 4.7-inch Gun Mks I, II, III, and IV were a family of British quick-firing 4.724-inch (120 mm) naval and coast defence guns of the late 1880s and 1890s that served with the navies of various countries. They were also mounted on various wheeled carriages to provide the British Army with a long range gun. They all had a barrel of 40 calibres length.
The QF 12-pounder 12-cwt gun (Quick-Firing) was a common, versatile 3-inch (76.2 mm) calibre naval gun introduced in 1894 and used until the middle of the 20th century. It was produced by Armstrong Whitworth, Elswick and used on Royal Navy warships, exported to allied countries, and used for land service. In British service "12-pounder" was the rounded value of the projectile weight, and "12 cwt (hundredweight)" was the weight of the barrel and breech, to differentiate it from other "12-pounder" guns.
The Ordnance QF Hotchkiss 6 pounder gun Mk I and Mk II or QF 6 pounder 8 cwt were a family of long-lived light 57 mm naval guns introduced in 1885 to defend against new, small and fast vessels such as torpedo boats and later submarines. There were many variants produced, often under license which ranged in length from 40 to 58 calibers, but 40 caliber was the most common version.
The QF 3-pounder Hotchkiss or in French use Canon Hotchkiss à tir rapide de 47 mm were a family of long-lived light 47 mm naval guns introduced in 1886 to defend against new, small and fast vessels such as torpedo boats and later submarines. There were many variants produced, often under license which ranged in length from 32 to 50 calibers but 40 caliber was the most common version. They were widely used by the navies of a number of nations and often used by both sides in a conflict. They were also used ashore as coastal defense guns and later as an anti-aircraft gun, whether on improvised or specialized HA/LA mounts.
The Armstrong Whitworth 12-inch naval gun of 40 calibres length was designed by and manufactured mainly by Armstrong's ordnance branch, Elswick Ordnance Company. It was intended for the Royal Navy's Royal Sovereign-class battleships, but budgetary constraints delayed their introduction. The first units were instead supplied to Japan. As the Type 41 12-inch (305 mm) 40-calibre naval gun it was the standard main battery on several early United Kingdom-built pre-dreadnought battleships of the Imperial Japanese Navy.
The Vickers 10 inch naval gun was used on battleships and armoured cruisers built during the first decade of the 20th century. They were used as the Type 41 10-inch /45-caliber aboard the British-built semi-dreadnought Katori-class battleships and the natively-built Satsuma-class battleships of the Imperial Japanese Navy.
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 BL 7.5-inch Mk II–Mk V guns were a variety of 50-calibre naval guns used by Britain in World War I. They all had similar performance and fired the same shells.
The BL 14 inch 45 calibre gun were various similar naval guns designed and manufactured by Elswick Ordnance Company to equip ships that Armstrong-Whitworth built and/or armed for several countries before World War I.
The EOC 12 inch 45 calibre gun were various similar 12-inch wire-wound naval guns designed and manufactured by Elswick Ordnance Company to equip ships that the parent company Armstrong Whitworth built and/or armed for several countries before World War I.
The Vickers 14 inch 45 calibre gun was designed and built by Vickers and initially installed on the battlecruiser Kongō which it was building for the Imperial Japanese Navy. Guns similar to this Vickers design were also later built in Japan to arm Kongō's sister ships and subsequent Japanese-constructed "super-dreadnoughts" which were all built in Japan. Japanese-built versions of the guns were designated 14 inch 41st Year Type, and from 1917 when the Navy went metric they were redesignated 36 cm 41st Year Type.
The QF 4.7 inch Gun Mark V originated as a 4.7 in (120 mm) 45-calibre naval gun designed by the Elswick Ordnance Company for export customers and known as the Pattern Y.
The Type 41 3-inch (76 mm) naval gun otherwise known as the 8 cm/40 3rd Year Type naval gun was a Japanese dual-purpose gun introduced before World War I. Although designated as 8 cm (3.15 in), its shells were 76.2 mm (3 in) in diameter.
By taking on ships being built for foreign navies in British shipyards, a number of British-built 6-inch 50-calibre naval guns found their way into British service in World War I. Their specifications and performance differed from standard Royal Navy 6-inch guns but in British service they fired standard service 100-pound projectiles.
The BL 6-inch Mk XXII gun was a British high-velocity 6-inch 50-calibre wire-wound naval guns deployed on the Nelson-class battleships from the 1920s to 1945.
The 305 mm /46 Model 1909 was a naval gun that was the main armament of two classes of Italian dreadnought battleships and one unique dreadnought of the Regia Marina built at the beginning of World War I. Many of these guns were later modified to 320 mm Model 1934 and 320 mm Model 1936 naval guns by boring out their barrels, adding new liners and developing new ammunition. A number of unconverted guns including those from the scrapped Dante Alighieri and the salvaged Leonardo da Vinci were also used as coastal artillery during World War II.
The Cannone da 190/45 was a family of Italian naval guns that were the secondary armament of two classes of armored cruisers of the Regia Marina and Hellenic Navy built before World War I. The cruisers that they were aboard saw action in both world wars. It is also believed that spare guns may have been used as coastal artillery during World War II.
The 15 cm/45 41st Year Type was a British naval gun designed by the Elswick Ordnance Company for export in the years before World War I that armed warships of the Imperial Japanese Navy. These guns served aboard Japanese ships during World War I and as coastal artillery during World War II.
Italy 
Empire of Japan 
United Kingdom