Infantry support weapon

Infantry support weapons are crew-served or individual weapons that provide firepower beyond that of standard rifles and carbines. They are typically organic to infantry units, meaning they are assigned directly to squads, platoons, or companies, and are used to suppress, neutralize, or destroy enemy targets. Their roles include providing suppressive fire, engaging point targets such as vehicles or bunkers, and delivering indirect fire in the case of mortars.

The category encompasses a wide range of systems, from light machine guns like the M249 SAW to heavier crew-served weapons like the M2 .50 caliber machine gun. Grenade launchers, such as the M203 or the automatic Mk 19, and portable mortars (60mm, 81mm, 120mm) are also classified as infantry support weapons. Recoilless rifles and anti-tank guided missiles (ATGMs) are sometimes included, though they are often considered separate categories.

The concept of infantry support weapons emerged in the late 19th century with the introduction of the Maxim gun, the first recoil-operated machine gun, which provided sustained firepower. During World War I, machine guns and light mortars became essential for trench warfare, and the need for portable firepower led to the development of submachine guns and light machine guns.

World War II saw the proliferation of general-purpose machine guns (GPMGs) like the German MG34 and MG42, which could be used in both light and heavy roles. The post-war era introduced the concept of the squad automatic weapon (SAW), such as the American M249, and the widespread adoption of grenade launchers. Modern developments include the use of programmable airburst munitions and the integration of fire control systems for increased accuracy.

Infantry support weapons can be categorized by their role and design. Machine guns are classified as light (e.g., M249), medium (e.g., M240), or heavy (e.g., M2). Grenade launchers include under-barrel models (M203), standalone single-shot (M79), and automatic (Mk 19). Mortars are portable, muzzle-loading weapons that fire high-arcing shells; common calibers are 60mm (M224), 81mm (M252), and 120mm (M120).

Recoilless rifles, such as the Carl Gustaf 8.4cm, provide a lightweight anti-armor and anti-fortification capability. Anti-tank guided missiles (ATGMs) like the Javelin are also used for infantry support, though they are often treated as a separate class. Each type has distinct advantages: machine guns offer sustained fire, grenade launchers provide a balance of explosive power and portability, and mortars deliver indirect fire with high trajectory.

Modern infantry support weapons are increasingly incorporating advanced technologies. Fire control systems with laser rangefinders, ballistic computers, and thermal sights are becoming standard on grenade launchers and automatic weapons, improving first-round hit probability. Programmable airburst munitions, such as the 40mm grenades used with the XM25, allow soldiers to detonate rounds above enemy positions in defilade.

Weight reduction is a key focus, with materials like titanium and polymers being used to lighten weapons without sacrificing durability. The development of lightweight machine guns, such as the M249's replacement, the M27 IAR, reflects a shift toward more mobile infantry. Additionally, the integration of suppressors and flash hiders reduces the signature of support weapons, enhancing stealth.

One lesser-known aspect is the use of infantry support weapons in urban warfare, where they are often employed for breaching and close-quarters combat. The M203 grenade launcher has been used to launch less-lethal munitions for riot control, and the M2 machine gun has been mounted on vehicles for convoy protection.

Another niche is the development of recoilless rifles with guided munitions, such as the Swedish Carl Gustaf M4, which can fire programmable rounds. Additionally, some armies have experimented with automatic mortars, like the British 51mm mortar, which can fire in semi-automatic mode. The role of support weapons in counter-insurgency operations has also led to the development of lightweight, accurate systems like the M320 grenade launcher module.

Crew-served weapon

A weapon that requires a team of two or more soldiers to operate effectively, such as a heavy machine gun or mortar.

Suppressive fire

Fire directed at an enemy to prevent them from moving, observing, or returning fire.

Indirect fire

Fire delivered at a target that is not visible to the shooter, typically using high-angle trajectories as with mortars.

Squad automatic weapon (SAW)

A light machine gun issued to a fire team to provide sustained automatic fire at the squad level.

Recoilless rifle

A lightweight firearm that vents propellant gases to the rear to eliminate recoil, allowing for larger projectiles.