i would grab the weapon stats on weapon initialisation store this in the weapon and pass it through to the projectile when you spawn it, this can be done by create the damage variable on the projectile and exposing it to spawn so it can be passed through by the weapon.
Im assuming that you want to store this table on an external database for balancing later, and if you make a call every time you fire the weapon, you will drive up your API costs.
Let me know if this makes sense/works for you? @Yosh.Ace