120mm mortar

In most modern armies, the 120mm mortar is the standard heavy mortar for indirect fire support in infantry units. They are high-angle, short-barreled weapons fired from a bipod or tripod mount. Heavier mortars are still seen in artillery units, primarily those following Soviet/Russian design. 120mm mortars may be revolutionized by the advent of guided shells.

To fire the weapon, a shell is dropped into the muzzle, falling to hit a firing pin at the base. They may fire from a hand-emplaced mount, or from a mortar carrier vehicle. Representative performance of the U.S. M120 (ground mounted) or M121 (vehicle mounted) systems, is:


 * Maximu range: 7200 meters
 * Minimum Range: 200 meters
 * Rate of fire: 16 rounds in the first minute and 4 rounds/minute in sustained fire
 * Ammunition types (unguided): High-explosive, smoke, illumination (both visible and infrared), training; high explosive rounds have a fuze settable for proximity, contact, or delayed contact.

Guided rounds
A U.S. Army requirement for the 120mm Accelerated Precision Mortar Initiative (APMI) set a minimum circular error probability of 10 meters and an objective of 5 meters, using Global Positioning System guidance. GPS guidance is preferred to laser guidance, so the weapon can engage targets behind obstacles, with no line of sight between the weapon and the target. Current laser rangefinders can easily read back GPS coordinates.