How to use mortars effectively?

[ConeHead]

Its the one weapon type I've avoided but they seem fun to use. problem is i feel like the enemies are too fast pace for the larger mortars to hit them with. Any tips?

[Julius Seizure]

Hoo boy, there's some layers to this one. The first point in their favor is that they can ignore all obstacles, but exactly how that helps you can differ from scenario to scenario.

They're perfectly viable 'assassination' weapons if you have sufficient distance and a flank, so taking heavy or high-value units out before engaging the rest of a group is a good starting point. Using them against groups of enemy armor that's aware of you is a little more complicated: in this scenario you have to learn to lead the target and fire at where you think they'll be grouping up instead of where they are. There's ways to manipulate this, such as using your tertiary weapons (Smoke, EMP) and finding a chokepoint to funnel them through, but there's a quirk to how enemies "hear" mortars you can also use.

Both the firing of a mortar and the impact of a shell have a report, but in both cases enemies will path to your vehicle; they'll never investigate the point of impact. You can use this to set up a one-two punch: fire a mortar where everyone will hear it, then back off to a safe distance and wait for them to investigate your last known position. It'll be like fish in a barrel.

The secondary use for mortars is as a demolition tool, and they're probably even better at this than they are at direct combat. Due to their sheer arc, a well-aimed shot will completely bypass any structures and obstacles between you and the Orbital Gun, Ammo Depot, last remaining wall between you and your evac point, etc. at any feasible distance.

In summary, using a mortar is sacrificing a certain amount of ease-of-use and close-range firepower, but you'll be able to hit everything you can see in an isometric game, which is something no other weapon type can offer.

[Reality]

Mortars took forever to appeal for me but there's one that really stands out

Use the Aux size mortar (Metronome) in a place like a street opening out of 2 walls -- and just keep shooting the same area - the fire rate and the constant noise it makes will cause enemies to continually stream out and get hammered. Pretty much every other Mortar will fire too slowly or have a super tiny ammo pool, but this leaves the fewest "gaps" of fast/tanky survivors of all mortars in the game. There doesn't need to be an "original victim" in the chokepoint, shooting a shot into the empty street is good enough to get the party started.

Also all Mortars you should STOP moving (turret movement is okay) before shooting, the aiming reticule needs a while to reach its small and accurate size

[Hara]

Originally posted by Reality:

Mortars took forever to appeal for me but there's one that really stands out

Use the Aux size mortar (Metronome) in a place like a street opening out of 2 walls -- and just keep shooting the same area - the fire rate and the constant noise it makes will cause enemies to continually stream out and get hammered. Pretty much every other Mortar will fire too slowly or have a super tiny ammo pool, but this leaves the fewest "gaps" of fast/tanky survivors of all mortars in the game. There doesn't need to be an "original victim" in the chokepoint, shooting a shot into the empty street is good enough to get the party started.

Also all Mortars you should STOP moving (turret movement is okay) before shooting, the aiming reticule needs a while to reach its small and accurate size

Movement doesn't affect accuracy at all if you use the arcs instead of ground cursor. Momentum is carried over to the projectile like the arc shows. You can use this to your advantage too.
The Gutterball, being an unique low-arc artillery, is easier to learn and abuse this mechanic with. It's possible to hit structures far off-screen by "shagohod'ing" artillery with the bull-rush of a tank.