It is the weaker of the two attachments compared to Missile Bay, though together they form a dangerous combination: Laser Gun can use Diffractive Laser and Atomic Rays, which hit all party members, and Missile Bay uses Launcher which can put all party members at low HP. Because Air Force will also use Diffractive Laser if one of its attachments are killed, it is best to kill Laser Gun second once Missile Bay is destroyed. Thundara spells work well. SummoningRamuh or Bismarck also has the chance to destroy both attachments at once.
A raygun is a type of fictional device that fires a beam of (usually) destructive energy used in science fiction; a form of directed-energy weapon. They have various alternate names: ray gun, death ray, beam gun, blaster, laser gun, phaser, zap gun etc. They are a well-known feature of science fiction; for such stories they typically have the general function of guns.