Railgun vs Gauss on PD fighters, considering enemy ECM

[imperator1550 (OP)]

On paper, Gauss are better than Railguns at Rate of Fire 8 onwards, if non-turreted.  For 150 tons you can have a Gauss cannon that shoots 8 shots with 50% accuracy each, or a railgun that shoots 4 shots with 100% accuracy.  The railgun takes up a bit more space with the power plant.

But what if the enemy has ECM? If the enemy 1 level of ECM advantage over you, that’s -10% to the hit chance, additive.  Then you get 8*40% = 3. 2 expected hits with the Gauss cannon, but 4*90%=3. 6 expected hits with the railgun.  Then isn’t the Gauss worse?

[Droll]

RoF 8 is the maximum tech for an unmodded game so I assume you mean ROF 5-8 as being "better" than railguns.

I don't recall the ECM % reduction mechanics but I think it's based on the base accuracy of the weapon.

So with a 1 lvl ecm disadvantage it would be 50% x 0.9 x 8 = 3.6 for the gauss and 100% x 0.9 x 4 = 3.6 for the railgun, which is the same.

[nuclearslurpee]

ECM reduction is applied before the reduction for Gauss gun size. Otherwise, however, ECM is a subtracted rather than multiplicative effect.

The expression for beam fire accuracy looks like this:

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ACC% = weapon_accuracy x [(BFC_tracking_speed * missile_tracking_bonus / target_speed) * (target_range - BFC_range) / BFC_range - 0.10 x (ECM_level - ECCM_level)]neglecting some boundary limits and the effect of Tactical officer skill, which I'm still uncertain where it fits into the formula. In any case, this ensures that all sizes of Gauss gun are equally capable against ECM, so Gauss is not at any disadvantage versus railguns from ECM.

However, until ROF 8 tech Gauss cannons are strictly inferior to railguns when not turreted (which is usually the case for fighters) in terms of expected damage/DPS per ton. The only exception to this is at very low tech levels when 10cm railguns with Capacitor 1 or 2 will not achieve ROF 5, but this is a pretty low bar to clear outside of conventional starts with low research rates so it is rarely relevant. Otherwise, Gauss is not competitive with railguns even at ROF 5 or 6 tech.