The First World War involved a vast range of weapons, many of which reflected the industrialisation of warfare. Infantry commonly used bolt action rifles, bayonets, pistols, hand grenades and machine guns. Artillery became the most destructive category of weapon and included field guns, howitzers, heavy artillery and mortars. Armies also introduced or expanded the use of poison gas, tanks, military aircraft, submarines and specialised naval weapons.
Cavalry remained in use, although its battlefield role changed because machine guns, barbed wire and artillery made traditional mounted charges increasingly vulnerable. Weapons differed between countries and evolved throughout the war as armies learned from battlefield experience. The conflict therefore cannot be understood through one dominant weapon; it was a system of interacting technologies.
The standard infantry rifle was the principal personal firearm for many soldiers. British troops commonly used the Short Magazine Lee Enfield, German troops used the Gewehr 98 and later variants, French troops used weapons including the Lebel Model 1886 and Berthier rifles, while Russian forces widely used the Mosin Nagant. These rifles were accurate at substantial distances and could fire significantly faster than many earlier military rifles. Bolt action mechanisms allowed soldiers to load individual cartridges into magazines and fire repeated shots. Bayonets could be attached for close combat, although popular imagery often exaggerates their importance in trench warfare. Pistols and revolvers were particularly useful for officers, cavalry and certain specialists.
Machine guns transformed battlefield tactics because they could deliver sustained automatic fire against infantry. Weapons such as the British Vickers, German Maschinengewehr 08 and French Hotchkiss provided powerful defensive fire. Machine guns were often mounted on tripods and positioned to create overlapping fields of fire. Their effectiveness increased when coordinated with artillery and obstacles such as barbed wire. Portable light machine guns were introduced or expanded later in the war, including the Lewis gun and Chauchat. These weapons gave infantry greater firepower and contributed to the difficulty of massed attacks. Machine guns were not completely invulnerable, however, because artillery could destroy their positions and infantry could capture or bypass them during successful assaults.
Artillery caused more battlefield casualties than small arms in many sectors and was central to First World War operations. Guns fired explosive, shrapnel, smoke and gas shells, while howitzers could fire at high angles against targets behind hills or fortifications. Heavy artillery was used to destroy defensive positions, communications and supply routes. Mortars provided shorter range indirect fire and were particularly useful against trenches. Artillery required sophisticated systems for observation, ranging, ammunition supply and coordination with infantry. Counterbattery fire attempted to locate and destroy enemy artillery. By 1917 and 1918, armies increasingly used predicted artillery fire, aerial observation and more precise coordination to improve effectiveness. The immense scale of artillery consumption reflected the industrial character of the war.
Grenades became important in trench warfare because they could be thrown into enemy trenches and dugouts without exposing the attacker to direct rifle fire for long periods. The British Mills bomb became one of the best known hand grenades, while Germany used several types including the Stielhandgranate. Rifle grenades extended the range of explosive projectiles available to infantry. Flamethrowers were also used, particularly by German forces, against fortified positions.
They produced intense heat and flame but had limited range and were dangerous for their operators. Mortars filled a tactical gap between hand grenades and artillery by providing relatively portable indirect fire against trench positions. These weapons were especially useful in the close and fortified environment of trench warfare.
Tanks were introduced by the British in 1916 as a response to the defensive power of trenches, barbed wire and machine guns. Early tanks were slow, mechanically unreliable and difficult to operate, but they could cross some trenches and obstacles that stopped infantry. The first major use occurred at the Battle of the Somme in September 1916. Later models became more effective, and British use of tanks at Cambrai in 1917 demonstrated the potential of concentrated armoured formations. France also developed significant tank forces, including the Renault FT, while Germany produced relatively few tanks during the war. Tanks became increasingly integrated with infantry and artillery tactics by 1918.
Aircraft developed rapidly during the conflict. At the beginning of the war they were primarily used for reconnaissance and artillery observation, but they later performed bombing, ground attack and fighter missions. Fighters were developed to protect reconnaissance aircraft and control the airspace above battlefields. Aircraft could photograph enemy positions and help artillery crews locate targets. Bombers attacked military and sometimes civilian targets at increasing ranges. Naval aviation also developed. At sea, submarines became particularly important, especially German U boats, which attacked Allied and neutral shipping in an attempt to disrupt supply lines. Naval mines, depth charges and anti submarine measures developed in response.
Chemical weapons included chlorine, phosgene and mustard gas, which were used to injure, incapacitate or kill enemy personnel. Chemical warfare was particularly associated with trench fighting because gases could enter dugouts and defensive positions. Armies responded by developing increasingly effective respirators, protective clothing, warning systems and tactical procedures. Weapons technology therefore evolved throughout the war as each side attempted to overcome the other's defences.
The First World War's weapon systems cannot be separated from industrial production, because artillery shells, rifles, machine guns, tanks, aircraft and chemical agents required large scale manufacturing and supply networks. The combination of weapons rather than any single invention produced the characteristic battlefield environment of industrial warfare, where firepower, logistics, engineering, intelligence and communications were closely interconnected.
