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.

The last ships to carry 6-pounders were the Aegir-class offshore patrol vessels of the Icelandic Coast Guard[citation needed] which replaced them in 1990 with the Bofors 40mm L/60 autocannon.

Argentina adopted the 40 calibre Hotchkiss 6-pounder in the 1890s, to arm its four Giuseppe Garibaldi-class armoured cruisers, purchased from Italy.

The former Brazilian coastal defence ship Marshal Deodoro was sold to Mexico in 1924 and renamed Anáhuac, which was retired in 1938.

The 6-pounder was the standard secondary and tertiary armament on most Japanese destroyers built between 1890 and 1920, and was still in service as late as the Pacific War.

[6] The Russians began purchasing 40 calibre 6-pounders from France starting in 1904 to replace its 3-pounder and 1-pounder guns in the anti-torpedo boat role.

[9] During World War I the navy required many more guns and an autofretted, mono-block barrel version was developed to simplify manufacture and identified as "6 pdr Single Tube".

Initially these guns were only allowed to be fired with a special lower charge, but in 1917 they were relined with A tubes as Mk I+++ which enabled them to use the standard 6-pounder ammunition.

The existing Hotchkiss 6-pounder naval gun appeared to most closely meet the need (a compact enough weapon to fit into a tank sponson with a sufficient high explosive shell).

The British chose to shorten the gun rather than change its location and replaced it in 1917 in the Mark IV tank onwards by the shorter QF 6 pounder 6 cwt Hotchkiss.

They are not listed as still being in service in this role at the end of the war,[10] presumably because German bombing attacks were conducted from relatively high altitudes which would have been beyond the gun's range.

The history of the Hotchkiss 6-pounder (called the Rapid Fire gun rather than Quick Firer in the US) in United States Navy and Army service is a complex story.

Oddly, one shipbuilding and naval supply company, Cramp & Sons, had a license to build both the Hotchkiss and Driggs-Schroeder and sold both to the Navy in parallel.

It appears that Hotchkiss type guns had an edge in production in the first half of the 1890s, but by 1895 Driggs-Schroeders were being produced in quantity to equip a considerable number of newly commissioned ships.

The initial purchases by the Navy were in small lots each year and there was no mass-production of these guns like one would see in smaller weapons.

However, USS Texas, a second class battleship commissioned in 1895, carried a mixed 6-pounder complement of ten Driggs-Schroeders and two Hotchkiss guns.

As the primary defender of coastal fortifications and harbours, the US Army had a need for lighter guns to supplement their shore batteries, particularly since land defence against infantry was a consideration in the 1890s.

[b] The Army was in an experimental phase like the Navy, testing new weapons in an era when military budgets were expanding after decades of Congressional stinginess.

However, 17 M1898 and all ten Mark II guns were transferred for use on Army troop transports in the Spanish–American War of 1898, leaving 70 weapons for land use.