Finland buys 100 Patria Tremos 120mm mortars to maximize firepower in Arctic conditions.

The Finnish Defence Forces and Patria finalized a €49.9 million serial procurement contract on September 8, 2026, for over 100 Patria Tremos 120 mm mobile mortar systems. Designated locally as the 120 KRH M3, these modular weapon integration modules are scheduled for delivery through 2028. The acquisition provides enhanced shoot-and-scoot mobility, reduces counter-battery exposure, and modernizes indirect fire support across all regional commands from Hanko to Lapland.

The contract covers the delivery of more than 100 vehicle-mounted smoothbore mortar systems featuring advanced hydro-pneumatic recoil technology that removes the need for ground support legs. Building on a pre-series batch delivered in 2025, the agreement includes options for hundreds of additional units to scale tactical infantry support nationwide.

Related topic: Patria and General Dynamics UK unveil new Ajax NEMO 120mm self-propelled mortar for armoured units

In Arctic conditions (characterized by deep snow, freezing temperatures, and rugged terrain), towed mortars can be extremely difficult to maneuver; the more mobile Patria Tremos therefore allows Finnish units to practice rapid "shoot-and-scoot" tactics. (Picture source: Patria)

On September 8, 2026, Finland approved the serial procurement of more than 100 Patria Tremos vehicle-mounted 120 mm mortar systems for €49.9 million excluding VAT, with deliveries in 2026-2028 and options for hundreds more. The first serial weapons, designated 120 KRH M3, are due in autumn 2026 after a pre-series batch delivered in 2025 entered conscript training in early 2026. The Tremos reaches more than 7 km depending on ammunition, compared with 7.5 km for the existing Tampella 120 M/92, nor does it increase peak firing rate because the M3 reaches 12 rounds/minute against 12-15 rounds/minute for the older mortar. The procurement therefore changes the tactical use of the weapon more than its ballistic envelope: the same 120 mm class of fire can be moved, emplaced, fired, and displaced in much less time and from a wider range of carriers.

The TREMOS can accommodate 81 mm or 120 mm tubes, but the 120 KRH M3 uses the 120 mm configuration with muzzle loading, manual ammunition handling, and manual laying. Finland possesses 822 heavy 120 mm mortars, so an acquisition of 100 M3s would equal 12.2% of that inventory by weapon count, while the actual first batch is larger. The Finnish M3 remains a muzzle-loaded, manually loaded, and manually laid 120 mm smoothbore mortar rather than an automatic turret. Traverse is ±185°, or 370° mechanically, with +40° to +80° firing elevation, while the weapon and integration module weigh 1,600 to 3,500 kg depending on configuration, compared with 500 kg for the complete 120 M/92. A three- or four-person crew consists of a commander, gunner, and one or two loaders, with crew seats, ammunition storage, and a preparation table integrated into the module. Existing 120 mm tubes, breeches, qualified ammunition and ballistic tables can remain in use, while an inertial navigation unit, weapon terminal and BMS connection can be added.

The hydro-pneumatic recoil mechanism is the main mechanical difference because it absorbs firing loads inside the mounting instead of transferring them through a baseplate into the ground. The Tremos consequently fires directly from its carrier without stabilizer legs or ground supports, a configuration Finland has tested from a Sisu A2045 off-road truck. It can be fitted to suitable 4×4, 6×6, 8×8 or light tracked carriers, while standardized container-type attachment points allow a forklift or front-end loader to transfer the module between vehicles within minutes. If a truck suffers an engine, transmission, axle, or suspension failure, a serviceable mortar module can therefore be transferred rather than remaining unavailable with the damaged vehicle. The mortar tube and command equipment can additionally be removed from the module for conventional ground firing, retaining a dismounted fallback mode.

The operational gain with the Tremos is measured mainly in exposure time. The Tremos can open fire in less than 30 seconds from a known position or less than 60 seconds from patrol mode, fire its first three rounds within 15 seconds, and reach 12 rounds/minute, equivalent to six rounds in 30 seconds, 12 in one minute, or 24 in two minutes per weapon. A three-round engagement can therefore progress from arrival to completion of the initial salvo in less than 45 seconds from a known position or less than 75 seconds from patrol mode. Because displacement can start immediately after the final round without recovering a baseplate, carriage, or stabilizers, the Tremos reduces the exposure window between arrival and departure, during which a firing position could be located increasingly quickly by the adversary's counter-battery radar, acoustic sensors, reconnaissance drones, and other systems able to locate firing points rapidly.

Finnish heavy-mortar organization magnifies that reduction in firing time because 120 mm weapons operate in three-mortar firing platoons, with three or four platoons forming companies of nine or 12 weapons. At 12 rounds/minute per 120 KRH M3, a platoon has a theoretical maximum output of 36 rounds/minute, a nine-weapon company 108 and a 12-weapon company 144, the latter figure also cited by Infantry Inspector Colonel Ari Mure. At the initial three-round-per-weapon rate, a platoon can fire nine rounds within 15 seconds, a nine-mortar company 27 rounds and a 12-mortar company 36 rounds. If maximum rate were maintained mathematically for two minutes, those formations would fire 72, 216, and 288 rounds respectively. Moreover, a digital fire direction can provide individual mortars with firing data accounting for weapon and target coordinates, weather, ammunition type, propellant temperature, and selected charge, allowing soldiers to occupy separate firing points while receiving firing data for the same target, reducing the risk of concentrating an entire mortar company in one location.

The 100-plus acquisition is consequently large enough to equip several formations. Exactly 100 systems could equip eight 12-weapon companies with four remaining, while 108 would equip nine companies and 120 would equip ten; those totals equal 12.2%, 13.1% and 14.6% respectively of Finland's 822 mortar inventory. If options eventually increased the fleet to 200 M3s, the equivalent would be 24.3% of the current heavy mortar inventory, while 300 would equal 36.5%, although Finland has not specified such quantities, but they show why the options for hundreds of additional M3s matter. Mure connected the requirement directly to nationwide coverage from Hanko to northern Lapland, implying a need for mobile heavy mortars across multiple formations and regions rather than only in a single specialized mortar formation.

The M3 also retains much of Finland's existing 120 mm logistics chain. The Tampella 120 M/92 weighs 500 kg, including a 100 kg tube, 70 kg support, 120 kg baseplate and 215 kg carriage, and combines a 2.0 m barrel with 0.25-7.5 km range and 12-15 rounds/minute. The Tremos raises installed mass to 1.6 to 3.5 tonnes but can reuse existing tubes, breeches, ammunition, and ballistic tables, so Finland gains vehicle mobility without introducing another mortar caliber or ammunition family. Fragmentation ammunition and specialized rounds such as smoke remain usable, with range adjusted through propellant charges fitted to the mortar bomb. Carrier and weapon maintenance can also be separated, so a mortar module can remain usable when its vehicle is unavailable, and a vehicle can be returned to other duties when the mortar module is removed.

Finland's geography gives this configuration a specific military rationale. The country extends 1,160 km from Hanko in the south to Nuorgam in the north and contains 168,000 lakes larger than 500 m² and 179,000 islands, producing a fragmented terrain network in which roads, forests, water obstacles and seasonal ground conditions vary sharply by region. In southern and central Finland, dense forests and lakes restrict long direct lines of fire and create numerous covered positions from which high-angle mortar trajectories can reach targets behind terrain or vegetation. In northern Finland, much greater distances between road networks, settlements and support areas increase the value of mounting the weapon directly on a vehicle rather than moving a 500 kg mortar and its separate components between firing positions. Snow, frozen ground and seasonal soft terrain also make a system that does not need a baseplate dug or settled into the firing position easier to move repeatedly during short fire missions. Compatibility with 4×4, 6×6, 8×8 and light tracked carriers allows units to select mobility according to local conditions rather than applying one vehicle solution across the entire country.

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Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, South Korea, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.