At 3/4 of travel distance, 'expodes' and launches 5(?) mines that land in an area around the round's predicted landing point. Target should be well ahead (5 seconds?/minimum firing radius) along the vector of the nearest enemy. Don't you love leaving nasty surprises around? :evilgrin:

Thanks, that's an interesting idea.. However, whether to predict target future location is a prototype stage property, which mean it will apply to entire turret (all ammo types), not just a specfic type of ammo. Alternatively, I could hack around and targeting via script, but script-controlled targeting is usually performance expensive and harder to implement, I need to think about the optimization and the proper way to make it works.

Also, dispersion should be a thing, whatever you fire from a mortar. If you look on page A-22 of FM 23-90 (https://www.marines.mil/Portals/1/Publications/FM%2023-90%20W%20CH%201.pdf), you'll see a dispersion table that you can use to calculate it.

(Because mortars are specifically intended to be able to fire past obstacles, they fire at 45-85 degrees, making the shell's ground speed rather slow, as they arc so high into the air. All of that extra travel time means that air pressure/wind/humidity/etc. plays a MUCH larger role in where a shell lands than with a regular cannon. You could even take all of that into account, so dispersion could change with the weather/etc., and mortar shell arcs could be different on different planets.)

Hm I can make certain ammo type less accurate, but it will bound to the ammo type and cannot be directly changed at runtime (e.g. depend on surface wind speed or scale with target distance). More dynamic change require scripting, and ya script is expensive :(

Fair enough. Different ammo types having different ballistic arcs & dispersion patterns would probably also be realistic.

Here's a thought: could you change the dispersion for any placed and/or stored mortars each startup? (The relatively small change in dispersion between pre-existing mortars and freshly made ones might not even be noticed, even if they are taken to another planet between game loads.)

I don't think I can technically do that.. factorio engine is quite limited in form of what can be done