Only fourteen were built and the Mk X, introduced in 1900 and incorporating a single-motion breech and changed rifling, succeeded them.

A total of 284 of the Mark X version were built by Vickers, of which 25 examples are known to survive today, all except one fitted on barbette mounts.

Immediately before the Second World War, an army team developed a surface-scanning radar to detect enemy ships in the English Channel.

The radar team noticed odd returns on their displays, and realised that these were due to the waterspouts caused by the shells exploding in the water creating a vertical surface off which the signals reflected.

There were several marks of mountings and a battery had extensive underground facilities in addition to the guns visible in their individual gun-pits.

Together with the 6-inch (152 mm) Mk VII, they provided the main heavy gun defence of the United Kingdom in World War I.

The ordnance and mounting together weighed some 125 tons, they were well balanced and the handwheels needed very little effort to move the gun.

Both were hydraulically powered and the platform was enclosed in a roofed gun house with three sides (and rear with Mark IX).

The three guns in the Imperial fortress colony of Bermuda remained in battery through the Second World War (and are still in situ), but were not actively utilised.

[17] From 1917 several Mk X guns were deployed ashore on the section of the Belgian coast still held by the Allies, near Nieuport.

The official opening of the restored De Waal Battery on Robben Island, near Cape Town, South Africa, took place on 4 March 2011.

Plans are afoot to restore the nearby Scala Battery at Simon's Town on the mainland as a static display.

[23] On Western Australia's Rottnest Island the H1 gun and associated underground resources are open to visitors as a static display.

On 10 December 1998 the Portuguese Coast Artillery fired the last shots from the 6th Battery of its "Fonte da Telha" 9.2-inch (23.4 cm) guns.

Shells up to and including World War I were not streamlined, typically having fairly blunt noses of 2 CRH.