QF 3-inch 20 cwt gun

The QF 3-inch 20 cwt was the British standard antiaircraft gun in the First World War and was used in the army, as well as in the navy and later on submarines.

When the First World War broke out, Britain had no anti-aircraft guns. When the German Empire occupied Belgium and northern France, the British cities came within the reach of German airships and thus in danger of being bombed.

In search of suitable guns, the British Navy initially supplied 18 of the QF 3-inch 20 cwt guns that they used on their warships. After detailed tests and comparisons with other guns, the British High Command decided that the range and penetration was sufficient, but some modifications were still necessary.

The original 3-inch (76 mm) QF cannon of the Navy was equipped with a vertical slide closure, which enabled a semi-automatic operation. Thus, the shutter opened after firing itself, let the empty shell jump out and remained open to be reloaded.

The anti-aircraft battalions newly deployed with this gun were initially occupied by naval soldiers of the Royal Naval Reserve, as they were already trained on the gun. After the Royal Garrison Artillery had trained himself, its soldiers took over the guns and occupied important positions on the British coast to the German airships and later to fight the bombers.

From November 1916, these guns were also used for air defense on the Western Front, after planes were increasingly used to combat ground targets. To make the guns more mobile, many of them were mounted on trucks. Of the 504 cannons produced during the First World War, 402 were deployed in the UK and 102 on the Western Front.

After the First World War, the guns were modernized over the years and assigned to the heavy anti-aircraft (HAA). With the introduction of the new 3.7-inch guns and the 40-mm Bofors guns, the 3-inch 20 cwt guns were replaced or converted into anti-tank guns. Some of the guns were also installed in Churchill tanks or left to the Royal Navy, which armed with destroyers and submarines.


QF 3-inch 20 cwt gun


QF 3-inch 20 cwt gun


A QF 3-inch 20 cwt gun mounted on a truck




Data sheet:

Designation: QF 3-inch 20 cwt gun
Country of Origin: Great Britain
Year: 1914
Number of pieces: around 504
Caliber: 76,2 mm
Tube length: 3,58 meters
Reach: Max. 7.200 meters
Mass: 5,99 tons



A QF 3-inch 20 cwt gun on the HMS Royal Oak


A QF 3-inch 20 cwt gun of the 99th Anti-Aircraft Regiment in Kent, May 1940


A QF 3-inch 20 cwt gun in a Churchill tank, 25 March 1943






You can find the right literature here:


British Artillery 1914–19: Field Army Artillery (New Vanguard)

British Artillery 1914–19: Field Army Artillery (New Vanguard) Paperback – March 25, 2004

In 1914 the artillery of Britain's 'Field Army' encompassed those weapons judged to have sufficient mobility to keep up with troops in the field. This book describes all major variants, from the 60-pdr guns of the heavy field batteries, perched somewhat uncomfortably on the cusp between field artillery and siege artillery, to the 2.75in. guns of the mountain batteries, almost toy-like in comparison. Between these two extremes lay the bulk of the artillery of the Field Army: the 13-pdr guns of the Royal Horse Artillery, and the 18-pdr guns and 4.5in. howitzers of the Royal Field Artillery batteries.

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British Artillery 1914–19: Heavy Artillery (New Vanguard)

British Artillery 1914–19: Heavy Artillery (New Vanguard) Paperback – August 10, 2005

World War I is often deemed to have been 'a war of artillery', and British heavy artillery played a vital part in destroying the German trenches and providing invaluable cover for advancing troops on the Western Front. This book details the huge guns of the Royal Garrison Artillery, including the 6-in. siege gun and howitzer, the 8-in. howitzer, the 12-in. railway and siege howitzer and the infamous 9.2-in breech-loading siege howitzer. Camouflage and enemy battery locations and transport are covered, as well as tactics used and how the guns were developed and manned.

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Artillery in the Great War

Artillery in the Great War Hardcover – May 18, 2011

Artillery was the decisive weapon of the Great War - it dominated the battlefields. Yet the history of artillery during the conflict has been neglected, and its impact on the fighting is inadequately understood. Paul Strong and Sanders Marble, in this important and highly readable study, seek to balance the account.Their work shows that artillery was central to the tactics of the belligerent nations throughout the long course of the conflict, in attack and in defense. They describe, in vivid detail, how in theory and practice the use of artillery developed in different ways among the opposing armies, and they reveal how artillery men on all sides coped with the extraordinary challenges that confronted them on the battlefield. They also give graphic accounts of the role played by artillery in specific operations, including the battles of Le Cateau, the Somme and Valenciennes.Their work will be fascinating reading for anyone who is keen to understand the impact of artillery

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World War I Battlefield Artillery Tactics (Elite)

World War I Battlefield Artillery Tactics (Elite) Paperback – December 9, 2014


From the beginning of 'trench warfare' in winter 1914/15, artillery became the absolutely dominant arm in all the major armies for the rest of World War I, to a degree never seen before or since. The numbers and capabilities of the guns and ammunition available governed all the generals' battle plans; and the ways in which they were employed, and either succeeded or failed, decided the outcome of battles. The majority of the millions of casualties suffered during the war fell victim to artillery fire.

The artillery war fell into three distinct phases along a four-year learning curve (with the necessary equipment and training for the second and third phases always lagging behind the tactical needs). The war began with mostly light, mobile artillery equipped and trained to support fast-moving infantry and cavalry by direct fire, mostly with air-bursting shrapnel shells.

The entirely unexpected end of the first campaigns of manoeuvre as the armies bogged down in static trench warfare found both sides ill equipped and ill trained for what was in essence siege warfare on an industrial scale. This demanded more and heavier guns and high-explosive shells, and more complex skills for indirect fire - observation on the ground and in the air, locating targets (including enemy artillery), dropping the right kind of shells on them, the communications needed for co-ordinating the work of hugely increased numbers of guns, and getting many millions of shells up to them for week-long bombardments. These seldom worked as anticipated (classically, by failing to 'cut the wire' or to penetrate deep bunkers); so innovative officers on both sides worked to devise new tactics, with more versatile mixes of ammunition (e.g. gas shells, smoke shells, star shells and so on) and more imaginative ways of using them, such as box barrages and creeping barrages.

Finally, in early 1918, the static slogging broke down into a renewed phase of manoeuvre warfare, made possible by sophisticated co-operation between artillery and infantry, plus the newly important air and mechanised forces. The lessons that were finally learned shaped the use of artillery worldwide for the rest of the 20th century.

Fully illustrated with period photographs and specially drawn colour artwork and drawing upon the latest research, this engaging study explains the rapid development of artillery tactics and techniques during the conflict in which artillery played a pre-eminent role - World War I.

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