[Vallen Chaos Valiant]

Ah, now I see.

Gunpower does exist in Code Geass, but it has fallen out of favour historically due to room temperature superconductor developments, allowing a variety of rail/gauss weapons to be efficently and practically produced and marketed.

It's like the bow and arrow; archery still exists in our world, we just don't use it as a common weapon any more.

(Oh, for people wondering; technologically we already have several potential designs for similar weapons, but it isn't as yet possible because the magnetic circuits would overheat and destroys itself either before or after a single shot.)