One disadvantage of the dismantling system was an inability to fire directly from the travelling carriage the way the BL 8 inch Howitzer could. In addition, the time required to bring the weapon into action was increased. However, the stability of the siege mounting made it "the most accurate of heavy howitzers".
In World War I British service, the gun served only on the Western Front with 36 British, one Australian and two Canadian batteries. Batteries increased in size from four guns to six during 1916–17. Initially, batteries were in Heavy Artillery Groups – usually a single battery of 9.2-inch with the other four batteries being differently equipped. Mid-war Groups were renamed Brigades RGA, and there were different types but the pattern of a single 9.2-inch battery in a brigade was retained.
During World War II, some guns went to France with the British Expeditionary Force, but their main deployment was in the United Kingdom as anti-invasion defences. According to the post-war memoirs of comedian Spike Milligan, who served in the Royal Artillery's 56th Heavy Regiment, 9.2-inch howitzer ammunition was so scarce in the early years of the Second World War that gun-crews in training were reduced to shouting 'bang' in unison, as no shells were available to practice with.
Bethlehem Steel was already contracted to manufacture 9.2-inch howitzers for Britain before the US entry into World War I in April 1917. The order was to be completed by July 1917 but they failed to meet the contract timescale and a year later deliveries had not been completed. As British manufacturing capacity increased, guns became available for export. The US government ordered 100 from Bethlehem and 132 from Britain to equip the American Expeditionary Forces building up in France. Sevellon Brown states that in fact Bethlehem did not reach production on the US order but that 40 were delivered from Britain by the end of the war.
The US Ordnance manual of 1920 describes its current stock of Model of 1917 (Vickers Mk I) and Model of 1918 (Vickers Mk II) as being built both in Britain and the USA. The US-built guns may have been British orders to Bethlehem which were redirected to the US Army.
Brown describes the US acquisition of the 9.2 as based mainly on the need at the time to utilize immediately available manufacturing capacities, and that development of a 240-mm howitzer based on the French Schneider 280-mm mortar for its super-heavy artillery was the main US goal. This view is supported by the 1920 US Ordnance manual which describes the 240 mm howitzer as far superior to the 9.2.
The US 65th Artillery Regiment, Coast Artillery Corps (C. A. C.), was in action with 9.2-inch howitzers in World War I. Also, the 72nd Regiment was almost ready for the front and the 50th Regiment was in France but had not commenced training at the time of the Armistice. Each regiment had an authorised strength of 24 guns.
Russian and Soviet service
Only four out of 44 9.2-inch howitzers promised by the allies ended up in the service of the Russian Empire. These four pieces were actually given by Japan in 1917. The Russian designation for the gun was 234-mm Vickers howitzer. An ammunition tally on 15 September 1917 showed 1,110 rounds per gun available in the Russian arsenal. There was however no local production of this ammunition, all had to be imported.
Three of the guns were still in service with the Soviet 317th artillery battalion, part of the 13th Army in the winter of 1939-1940, when they were employed against the Mannerheim Line.