[Suicide Junkie]

Keep in mind that the ranges are only 2-4 for these capital ship weapons. The zero-point will be in the middle, too.

So the 20 and 40 mm guns should have some chance of hitting fighters, and the 100mm gun should have about 40% to-hit even at the doubled max range.
Also, the additional punch of the big guns will be more effective than it looks, since the captial ships will be using leaky shields. The smaller guns will end up doing no damage to most capital ships, and much of the medium guns' damage will be negated.