It always struck me as wierd that the description of the Meson gun:
"The meson blaster is a unique, powerful gun that utilises subatomic particles with a short half-life. These particles, called mesons, are accelerated and flung toward a target. The most damage occurs once the particles decay inside the target - they cause internal explosions and give off radiation. Energised shields can stop these particles, and atmospheric conditions render this gun ineffective." says quite clearly that this gun is not suitable for atmospheric conditions
Yet the only kilrathi fighter that is made specifically for atmospheric conditions (Ekapshi) has Meson guns mounted on it. A silly contradiction, Origin!