The L81 mortar: build it, aim it, move it
The mortar is a building, not a purchase. What it takes to put one up, what its sight will and will not tell you, and when it beats the howitzer.
It is a building
The vendor does not sell a mortar. The L81 is an emplacement built inside a Forward Operating Base's radius, and it fires the FOB's Ammo Supplies, which the vendor card describes as the resource for reloading buildable weapons. The shopping list is the FOB kit at $2,500, Build Supplies at $10 a unit, and a Large Hammer. The Handbook says anti-air emplacements, mortars and the sturdiest walls all need the Large Hammer; the Hub's Support guide puts it at Support level 7, a $25,000 unlock and $1,600 at the vendor. The FOB ships with a Small and a Medium Hammer inside, so the first base needs no hammer purchase, but those two only raise walls, gates and doors.
Putting it up
Place the FOB where it can reach the fight without being in it; its build radius appears on the minimap once it is down. Building draws from the Build Supplies stockpile, which starts at 1,250, tops up at $10 a unit from the terminal and caps at 20,000. Nobody has published what the tube costs in supplies; Wardogs Zone's base builder bills it at 121 against 61 for a Hesco wall, one site's figure and unverified. Hammering the yellow marker during a build speeds it up several times over, and every swing pays: $1 a hit, $6 for the marked hit, $15 on completion, all with Support XP. On the build tool R rotates, B toggles snapping and V dismantles.
Aiming it
One trajectory, high only, so there is one elevation per distance and nothing to choose. The sight runs 150 to 850 mil on its own scale. How far that reaches is the most disputed number in the game. The table behind our solver covers 132 to 684 m; another community calculator publishes about 3.1 km for the same weapon; Wardogs Zone's board says roughly 50 to 700 m; Bulkhead has said nothing. The Hub's advice stands: build it, fire one round at something you can see, pace the result.
Whatever the ceiling, the tube groups about 50 MOA, under 2 m at 132 m and around 10 m at 684 m, so it is a precise weapon at 200 m and an area weapon at range. Aim at the middle of a group, never at one person. Fire one, take the spotter's correction in metres, then fire for effect; Wardogs Zone lists a 6.5 second reload against the SPH-2's 27, which is what makes walking rounds practical. Expect a dead circle of about 50 m around the tube that no elevation can reach.
When it beats the SPH-2
It costs supplies instead of $8,000, three crew, level 55 and a $400,000 unlock, and it sits where your FOB is, so it is the artillery you actually have in most matches. Its slow, steep shell is wrong for anything moving and right for anything that cannot leave: a rooftop, a tower terminal, a held building, a dug-in FOB. Wardogs HQ adds that buildings are destructible, so sustained fire does not need to hit anyone; removing the structure does the job. Pressure that moves people off a position is worth more than the kills, because moving people are people your rifles can shoot.
The tube does not move; you do
Firing tells the enemy where the FOB is as clearly as where you are aiming, and a mortar cannot run. Its survival is a fortification problem: overhead cover (the buildables list carries three tiers of Indirect Fire Shelter), defenders, and a second mortar position built before the first is found, which is Wardogs HQ's counter-battery advice. Watch the ammunition too. A fresh FOB holds only 100 Ammo Supplies, and no source says how many rounds a unit buys.