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Finnish AMV with AMOS mortar turret
|Type||Twin-barrel, self-loading mortar system|
|Place of origin||Finland/Sweden|
|Used by||Finnish Army, Swedish Army|
|Designer||Patria Vammas Oy, Alvis Hägglunds AB|
|Designed||started in 1995|
|Weight||4,445 kg (turret only)|
|Barrel length||3000 mm|
|Crew||1+3 (vehicle-fit, 2 in turret)|
|Shell||Standard mortar smoothbore + stub case or smart guided ammunition. Typically HE|
|Caliber||2 × 120 mm smoothbore|
|Elevation||−3° to +85°, electrical/manual|
|Traverse||± 360°, electrical/manual|
|Rate of fire||16/12 rds/min (max/sustained), first 4 <8 sec, MRSI 2 × 8|
|Effective firing range||6–10 km (ammo dependent)|
|Maximum firing range||
10 km (indirect fire)|
150–1,550 m (direct fire)
AMOS or Advanced Mortar System is a 120 mm automatic twin barrelled, breech loaded mortar turret. AMOS has been fitted to a wide range of armoured vehicles, such as the Sisu Pasi, Patria AMV and Combat Vehicle 90. The Swedish Navy originally planned to fit AMOS to the CB90 assault craft, but found that it was too small to carry it. Instead, a project to develop the larger Combat Boat 2010 was launched specifically to carry AMOS.
When fitted to a vehicle, both GPS- and inertia positioning are used. The electronic fire-control system utilises digital maps. The twin barrelled AMOS is able to keep up rate of fire of 12 rounds per minute. Using its computer-controlled MRSI feature (multiple rounds simultaneous impact) it is possible to set up a burst of up to 16 rounds that hit the target simultaneously. The first rounds are fired at higher angles with more propellant so that the rounds fly in a high arc. The next rounds are shot later with a slightly smaller angle and less propellant so that they fly a lower arc to the same target. This can be done seven times in a row, always adjusting the angle and power. The adjustment between shots is done by a computer. The strike of one AMOS unit roughly equals one strike of an artillery battery.
An AMOS turret has a full 360-degree field of fire at elevations of −3 to +85 degrees. AMOS is capable of both conventional indirect fire and direct fire for self-protection. In a typical installation, mounted on a Patria AMV or a similar vehicle, the vehicle can dash to the next position roughly 30 seconds after initiating the 14-round salvo, leaving minimal time for detection and counter-attack by enemy; evasion is the primary means of self-protection.
AMOS is manufactured and marketed by Finnish/Swedish Patria Hägglunds, a joint venture between Finnish Patria and Swedish BAE Systems Hägglunds. The system is known as the SSG120 in Swedish service. Ammunition for AMOS includes the Strix guided round and a modification of the Spanish Instalaza 120 mm Mortar Cargo Round "MAT-120" (although the latter is restricted from the Finnish inventory because of Finnish partnership in the program abolishing landmines). Because AMOS is breech-loading, it cannot fire standard muzzle-loaded mortar rounds. AMOS rounds feature a "short stub case" at the base of the fins, similar to a sabot. In this way, expended rounds fired by AMOS can be easily differentiated from traditional mortar systems.