So it’s supposed to reduce the optimal range of turrets, right? Dark Matter in the context of this game is said to absorb EM radiation. Okay. For blasters and energy weapons this makes sense.
For railguns and projectiles, it does not. In both cases, these are physical slugs being fired out of a cannon, which detonate on impact.
My proposal is thus: change the deleterious effect of Dark Matter filaments, such that instead of affecting turret optimal ranges, it puts a penalty towards targeting range.
If you think about it, this makes more sense. To even achieve a target lock requires the use of some form of EM radiation. This effect would also play nicely with the current secondary effect, which is an increase in ship velocity. This also technically keeps the current effect, which is to reduce the effective range of weapons.
Missiles should get a velocity bonus owing to the fact that they have their own propulsion, as do ships.