Suppressive fire
[2] Suppressive fire usually achieves its effect by threatening casualties to individuals who expose themselves to it, forcing them to inactivity and ineffectiveness by keeping their heads down, 'or else take a bullet'.
However, suppressive fire may be used against indirect firers, enemy air defenses or other military activities such as construction work or logistic activities, or to deny an area to the enemy for a short period of time (it is unsuitable for prolonged area denial due to ammunition supply constraints).
Suppressive fire is a tactic to reduce casualties to friendly forces and enable them to conduct their immediate mission.
NATO also defines 'suppression of enemy air defenses' (SEAD), which has a broader definition and includes materiel damage.
However, depending on factors including the type of ammunition and the target's protection, suppressive fire may cause casualties and/or damage to enemy equipment.
Weapons vary widely in their suppressive capabilities, which are the threat signaled by the noise of projectiles in flight and their impact.
World War I marked a steep change because of the development of artillery techniques and the protection provided by trenches.
A moving barrage could suppress a line of front providing covering fire for an attack several miles wide.
In World War II amphibious assaults, naval warships would open fire with their main armaments at known or suspected enemy artillery, mortar, or machine gun positions, on or behind the landing beaches, to suppress enemy fire from these positions which could be directed against the landing troops.
In World War I a moving barrage was the normal method; shrapnel shells were fired to place their bullet cone ahead of the advancing infantry with their aimpoints moved 100 yard further forward every few minutes on a front of several kilometres to support an attack by several divisions or corps.
High Explosive (HE) barrages were also used in World War II, including to cover the advance of tanks by suppressing anti-tank gunners.
This orders every gun in any concerned battery to immediately fire whatever round and fuse is loaded, possibly from someone else's, or more than one callsign's mission.
However, limited ammunition loads mean that such systems are better suited to destructive fire against precisely identified targets unless the required suppression time period is short.
In Afghanistan, the Mujahideen often modified RPG-7 rocket launchers for use against Russian helicopters by adding a curved pipe to the end of the blast tube, which diverted the backblast, allowing the RPG to be fired upward at aircraft from a prone position.
At the time, Soviet helicopters countered the threat from RPGs at landing zones by first clearing them with saturation anti-personnel suppression fire from machine guns.
The Russians used the Dragunov sniper rifle at the platoon level for providing special long-distance disrupting and suppressive fire on the battlefield, even with sudden close encounters with enemy troops in mind.
