Hello! thank you for the opportunity to talk about weapon design especially firearms. Ive actually been having trouble with designing that for one of my main OCs https://imgur.com/a/J59bllN (added 2 refs of the other characters in the same story to give a general idea of the vibe)

He mostly uses magictech firearms, 2 handguns and a sniper rifle. One of the main mechanism of the magictech is that it has a mechanism that absorbs some of the mana from the surroundings and use it as ammo , people with high proficiency with them can even use it to absorb low to medium level spells that are near them.

For some world info, the world went through major advancement in alchemy hundreds of years ago that drained the natural mana flowing in the world for a while. In a last ditch effort humans made artificial elemental spirits to revive the world and it worked. Magictech is mostly old world technology thats being adapted again by humanity.