Machine gun in the context of Fully automatic

Modern warfare is warfare that diverges notably from previous military concepts, methods, and technology, emphasizing how combatants must modernize to preserve their battle worthiness. As such, it is an evolving subject, seen differently in different times and places. In its narrowest sense, it is merely a synonym for contemporary warfare.

In its widest sense, it includes all warfare since the "gunpowder revolution" that marks the start of early modern warfare, but other landmark military developments have been used instead, including the emphasis of artillery marked by the Crimean War, the military reliance on railways beginning with the American Civil War, the launch of the first dreadnought in 1905, or the use of the machine gun, aircraft, tank, or radio in World War I.

A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and battlefield mobility provided by tracks and a powerful engine; their main armament is often mounted within a turret. They are a mainstay of modern 20th and 21st century ground forces and a key part of combined arms combat.

Modern tanks are versatile mobile land weapons platforms whose main armament is a large-calibre tank gun mounted in a rotating gun turret, supplemented by machine guns or other ranged weapons such as anti-tank guided missiles or rocket launchers. They have heavy vehicle armour which provides protection for the crew, the vehicle's munition storage, fuel tank and propulsion systems. The use of tracks rather than wheels provides improved operational mobility which allows the tank to overcome rugged terrain and adverse conditions such as mud and ice/snow better than wheeled vehicles, and thus be more flexibly positioned at advantageous locations on the battlefield. These features enable the tank to perform in a variety of intense combat situations, simultaneously both offensively (with direct fire from their powerful main gun) and defensively (as fire support and defilade for friendly troops due to the near invulnerability to common infantry small arms and good resistance against heavier weapons, although anti-tank weapons used in 2022, some of them man-portable, have demonstrated the ability to destroy older generations of tanks with single shots), all while maintaining the mobility needed to exploit changing tactical situations. Fully integrating tanks into modern military forces spawned a new era of combat called armoured warfare.

A spitzer bullet (from German Spitzgeschoss 'point shot') is a munitions term, primarily regarding fully-powered and intermediate small-arms ammunition, describing bullets featuring an aerodynamically pointed nose shape, called a spire point, sometimes combined with a tapered base, called a boat tail (then a spitzer boat-tail bullet), in order to reduce drag and obtain a lower drag coefficient, resulting in an aerodynamically superior torpedo shaped projectile, which decelerates less rapidly and has improved external ballistic behaviour, at the expense of some potential weight and kinetic energy relative to blunter ogive/round/flat-nose flat-base projectiles.

The type was developed for military purposes in the late 19th and early 20th century and was a major design improvement compared to earlier rounder or flatter-tipped bullets in terms of range and accuracy. Its introduction, along with long-range volley sights for service rifles, changed military doctrines. Area targets at ranges up to 1,420–2,606 m (1,550–2,850 yd) could be subject to rifle fire. With improvements in machine guns at the turn of the 20th century, the addition of clinometers meant that fixed machine gun squads could deliver plunging fire or indirect fire at more than 3,000 m (3,280 yd). The indirect firing method exploits the maximal effective range, that is defined by the maximum range of a small-arms projectile while still maintaining the minimum kinetic energy required to put unprotected personnel out of action, which is generally believed to be 15 kilogram-meters (147 J / 108 ft⋅lbf).

An airstrike, air strike, or air raid is an offensive operation against ground or sea surface targets carried out by aircraft, such as military balloons, airships, attack aircraft, bombers, gunships, attack helicopters and attack drones. The official definition of an airstrike includes all sorts of targets, including low-altitude air targets, but in popular usage the term is usually narrowed to a tactical (small-scale) strafing, missile strike or tactical bombing on a specific army, militia or naval position, as opposed to a larger, more generalized and indiscriminate attack against an entire area such as carpet bombing and strategic bombing.

Weapons used in an airstrike can range from aircraft-mounted direct-fire cannons and machine guns, rockets and air-to-surface missiles, to various types of aerial bombs (both unguided and guided), glide bombs, air-launched cruise missiles, and even directed-energy weapons such as laser weapons.

Close air support (CAS) is defined as aerial warfare actions—often air-to-ground actions such as strafes or airstrikes—by military aircraft against hostile targets in close proximity to friendly forces. A form of fire support, CAS requires detailed integration of each air mission with fire and movement of all forces involved. CAS may be conducted using aerial bombs, glide bombs, missiles, rockets, autocannons, machine guns, and even directed-energy weapons such as lasers.

The requirement for detailed integration because of proximity, fires or movement is the determining factor. CAS may need to be conducted during shaping operations with special forces if the mission requires detailed integration with the fire and movement of those forces. A closely related subset of air interdiction, battlefield air interdiction, denotes interdiction against units with near-term effects on friendly units, but which does not require integration with friendly troop movements. CAS requires excellent coordination with ground forces, typically handled by specialists such as artillery observers, joint terminal attack controllers, and forward air controllers.

Saturation fire is a saturation attack using an intense level of artillery bombardment or rapid direct fire (from automatic weapons such as machine guns, autocannons or rotary guns) that is designed to overwhelm a target area with lethal firepower, for the purpose of suppression, area denial or mass destruction of the enemy.

Mobility in military terms refers to the ability of a weapon system, combat unit or armed force to move toward a military objective. Combat forces with a higher mobility are able to move more quickly, and/or across more hostile terrain, than forces with lower mobility.

Mobility is regarded as a vital component of the modern battlefield, as the ability to deliver weapon systems or combat units to their objective quickly can often mean the difference between victory and defeat. Armies around the world have massively increased their mobility over the last 100 years. In World War I, for example, most combat units could move on the battlefield only as fast as a soldier could walk. In the face of overwhelming firepower presented by machine guns and artillery, that resulted in stalemate and an inability to outmaneuver the enemy. By World War II, battlefield mobility had greatly improved with the development of the tank, and with tracked and other mechanized vehicles, to move forces to, from, along and across the battlefront even under fire.

A submachine gun (SMG) or sub-gun is a magazine-fed automatic carbine designed to fire handgun cartridges. The term "submachine gun" was coined by John T. Thompson, the inventor of the Thompson submachine gun, to describe its design concept as an automatic firearm with notably less firepower than a machine gun (hence the prefix "sub-"). As a machine gun must fire rifle cartridges to be classified as such, submachine guns are not considered machine guns.

In the 20th century, the submachine gun was developed during World War I (1914–1918) as a close quarter offensive weapon, mainly for trench raiding. At its peak during World War II (1939–1945), millions of submachine guns were made for assault troops and auxiliaries whose doctrines emphasized close-quarter suppressive fire. New submachine gun designs appeared frequently during the Cold War, especially among special forces, commandos and mechanized infantrymen. Submachine gun usage for frontline combat decreased in the 1980s and 1990s.

A handgun is a firearm designed to be usable with only one hand. It is distinguished from a long barreled gun (i.e., carbine, rifle, shotgun, submachine gun, or machine gun) which typically is intended to be held by both hands and braced against the shoulder. Handguns have shorter effective ranges compared to long guns, and are much harder to shoot accurately. While most early handguns are single-shot pistols, the two most common types of handguns used in modern times are revolvers and semi-automatic pistols.

Before commercial mass production, handguns were often considered a badge of office — comparable to a ceremonial sword – as they had limited utility and were more expensive than the long barreled guns of the era. In 1836, Samuel Colt patented the Colt Paterson, the first practical mass-produced revolver, which was capable of firing five shots in rapid succession and quickly became a popular personal weapon, giving rise to the saying, "God created men, but Colt made them equal."

The Chaco War (Spanish: Guerra del Chaco, Guarani: Cháko Ñorairõ) was fought from 1932 to 1935. It was between Bolivia and Paraguay over control of the northern part of the Gran Chaco region (known in Spanish as the Chaco Boreal), which was thought to be rich in petroleum. The war is also referred to as La Guerra de la Sed (Spanish for "The War of Thirst"), since it was fought in the semi-arid Chaco. It was the first South America war in which modern weapons (such as machine guns, armoured fighting vehicles and airplanes) were used, and also the bloodiest South America war of the 20th century — around 2% of the Bolivian population and 3% of Paraguayans were killed during the conflict.

During the war, both landlocked countries faced difficulties moving arms and supplies through neighbouring countries. Despite its income from mining and a larger and better-equipped army, problems with international trade and poor internal communications ultimately turned the tide against Bolivia. The war concluded at the Chaco Peace Conference in Buenos Aires in July 1938, at which both countries signed a peace treaty awarding three-quarters of the Gran Chaco to Paraguay.

The Battle of Dibrivka was a military conflict between Ukrainian insurgents, led by Nestor Makhno and Fedir Shchus, and the Central Powers that were occupying southern Ukraine. It took place on 30 September 1918, towards the end of World War I. The battle began when Makhno, Shchus, and a group of anarchist supporters ambushed Austrian and Ukrainian detachments stationed in Dibrivka. The anarchists were armed with machine guns and were assisted by local peasants, who together captured ammunition, arms, and prisoners of war. It resulted in an insurgent victory and the establishment of an autonomous territory in the region, following the subsequent defeat of the Central Powers.

A weapons platform is generally any structure, vehicle or mechanism on which a weapon can be installed (via various mounting mechanisms) for optimal stability and performance. The mounted weapons, the platform and all other associated supporting equipments together form the weapon system.

In more general use, a weapons platform could be structured around a gun, such as a gun turret on a ship, or bracing on an aircraft. For example, a jet aircraft is a weapons platform for missiles, bombs or autocannons, and the resultant weapon system is the fighter jet; a motorboat can serve as a weapons platform for automatic weapons, torpedoes and flamethrowers, resulting in weapon systems such as gunboats and fast attack crafts. Land vehicles, either wheeled, tracked or mixed, are also considered weapons platforms for grenade launchers, machine guns, recoilless guns and some missile launchers, which transform the vehicles into weapon systems such as armored cars (such as the Humvee), IFVs and technicals (improvised from civilian pickup trucks). In addition, artificial satellites have been proposed as potential space weapon platforms. These satellites could carry an arsenal of weapons, such as to threaten other countries with the possibility of an orbital nuclear strike (see Rods from God).

Air-to-ground weaponry is aircraft ordnance used by combat aircraft to attack ground targets. The weapons include bombs, machine guns, autocannons, air-to-surface missiles, rockets, air-launched cruise missiles and grenade launchers.

An autocannon, automatic cannon, machine cannon or anti-tank machine gun, is a fully automatic gun that is capable of rapid-firing large-caliber (20 mm/0.79 in or more) armour-piercing, explosive or incendiary shells, as opposed to the smaller-caliber kinetic projectiles (bullets) fired by a machine gun. Autocannons have a longer effective range and greater terminal performance than machine guns, due to the use of larger/heavier munitions (most often in the range of 20–60 mm (0.79–2.36 in), but bigger calibers also exist), but are usually smaller than tank guns, howitzers, field guns, or other artillery. When used on its own, the word "autocannon" typically indicates a non-rotary weapon with a single barrel. When multiple rotating barrels are involved, such a weapon is referred to as a "rotary autocannon" or "rotary cannon". If it uses a single barrel with a rotating cylinder with multiple chambers, it is known as a "revolver autocannon" or "revolver cannon"; both of these systems are commonly used as aircraft guns and anti-aircraft guns.

Autocannons are heavy weapons that are unsuitable for use by infantry. Due to the heavy weight and recoil, they are typically installed on fixed mounts, wheeled carriages, ground combat vehicles, aircraft, or watercraft, and are almost always crew-served, or even remote-operated with automatic target recognition/acquisition (e.g. sentry guns and naval CIWS). As such, ammunition is typically fed from a belt system to reduce reloading pauses or for a faster rate of fire, but magazines remain an option. Common types of ammunition, among a wide variety, include HEIAP, HEDP and more specialised armour-piercing (AP) munitions, mainly composite rigid (APCR) and discarding sabot (APDS) rounds.

The combat box was a tactical formation used by heavy (strategic) bombers of the U.S. Army Air Forces during World War II. The combat box was also referred to as a "staggered formation". Its defensive purpose was in massing the firepower of the bombers' guns, while offensively it concentrated the release of bombs on a target.

Initially formations were created in keeping with the pre-war Air Corps doctrine that massed bombers could attack and destroy targets in daylight without fighter escort, relying on interlocking fire from their defensive machine guns, almost exclusively the "light barrel" Browning AN/M2 .50 calibre (12.7 mm) gun. However the use of high altitudes by USAAF bombers resulted in factors that demanded a tighter bomb pattern and the combat box continued in use even after the advent of fighter escort largely mitigated the threat of fighter interception. It was especially used over Europe during and after the spring of 1944, with USAAF fighters flying far ahead of the combat boxes in air supremacy mode instead against the Luftwaffe's fighters.

A light bomber is a relatively small and fast type of military bomber aircraft that was primarily employed before the 1950s. Such aircraft would typically not carry more than one ton of ordnance.

The earliest light bombers were intended to drop their bombs in level flight over a target. During World War I some air forces began to distinguish between light bombers and the earliest purpose-built attack aircraft which carried out ground attack, close air support, anti-shipping and similar missions. After World War I, attack aircraft were typically identifiable by their ability to carry multiple fixed machine guns, automatic cannons and rockets in addition to bombs. Light bombers have often served as attack aircraft and vice versa.

The Metaxas Line (Greek: Γραμμή Μεταξά, Grammi Metaxa) was a chain of fortifications constructed along the line of the Greco-Bulgarian border, designed to protect Greece in case of a Bulgarian invasion after the rearmament of Bulgaria. It was named after Ioannis Metaxas, then Prime Minister of Greece, and chiefly consists of tunnels that led to observatories, emplacements and machine gun nests. The constructions are so sturdy that they survive to this day, some of which are still in active service. Some of them are open to the public.

The Metaxas Line consists of 21 independent fortification complexes, the largest of which is Fort Roupel as it covers 6.1 out of the 155 km of the full line and had been constructed at a height of 322 m. Illumination was initially mostly provided by oil-lamps, although generators were also installed. Currently, the fortifications are supplied with public electricity, but they are also equipped with generators. Ventilation was achieved both naturally and artificially. Water was supplied via water-mains. The fortification works lasted four years and their cost at the time reached 100,400,000 drachmas.