Overall Length: 3 ft 9.5 in.
Muzzle velocity (HE): 700 f.p.s.
Rate of Fire: 18 rounds/min norm; 30-35 rpm max
Rocket: M7A1 shaped charge,rocket motor ignited electrically
Maximum Range (HE): 3290 yds
Sight: M4
Each round has fins to stabilize it in flight and cause it to strike fuze-end first. The propelling charge consists of a primer, an ignition cartridge, and four or six removable propellent increments. The primer and ignition cartridge are inserted in the base of the fin shaft. The removable increments are between the fin blades or the boom assembly and the number used assists in determining range. The projectile is dropped down the barrel, fin end first, the primer strikes the fixed firing pin which detonates the primer and ignition cartridge, which in turn ignites the propellent increments, forcing the round out of the barrel, carrying the primer and cartridge with it and readying the mortar for the next round.
A mortar may be used in two formats, Direct Fire and Indirect Fire.
Direct fire is line-of-sight firing and uses the M4 sight on the Mortar itself. This requires two people; a Gunner and a Loader.
Indirect Fire is called in by radio over distances further than the gunner can see. A Forward Observer who sees the target plots it on a map and sends coordinates to the Fire Direction Control personnel who plots this on a map. The Fire Controller converts that data into numbers and gives them to the gunner dials into the sight before firing. The Fire Controller also tells the Loader how many powder bags to remove.
Indirect Fire rarely hits first time. The rounds are then walked onto the target with the Forward Observer calling in corrections to the Fire Controller. In this case, the Fire Controller and the Forward Observer are the personnel who determine accuracy. This format requires four people; the Forward Observer, the Fire Controller, the Gunner, and the Loader.
Ammunition:
81mm M374A2 High Explosive
Weight: 4.23kg
Minimum Range: 72m
Effective Range: 4,595m
Maximum Range: 4, 595m
Burst Radius: 34m
Packaging: 3 rds per case
Package Weight: 23.13kg
A high explosive round that is used against unarmored targets and personnel. The round, on impact, explodes into fragments (E=6) throughout the burst radius. The explosion will blast through .8 meters of concrete or 1.1 meters of rock.
81mm M375A4 White Phosphorous
Weight: 4.23kg
Minimum Range: 72m
Effective Range: 4,737m
Maximum Range: 4,737m
Burst Radius: 20m
Packaging: 3 rds per case
Package Weight: 23.13kg
This shell is used for smoke, anti-personnel, and incendiary uses. It contains White Phosphorous which will burn at 2,700*C for 120 seconds in particles spread throughout the burst radius. The explosion and burning of the shell creates a very dense cloud of white smoke.
81mm M301A3 Illuminating
Weight: 4.89kg
Minimum Range: 100m
Effective Range: 3,150m
Maximum Range: 3,150m
Burst Radius: 1,200m
Packaging: 3rds per case
Package Weight: 24.94kg
Also known as a Star Shell, this round upon functioning ejects a white magnesium flare on a parachute. The flare illuminates a 1,200 meter area with 500,000 candlepower for 75 seconds. The fuse of the round is adjustable for what altitude the round will function at. The round can also be set to function on impact, in which case the magnesium will burn at 1,980*C, igniting most flammable materials within one meter of impact.