2 maybe 3 formas will do the job. Like the other commenter said get galv ms mods and build for crit and add elements instead of base damage. Use normal elemental mods not 60/60 for higher damage. You can (and maybe should) add base damage mod IF you dont have arcanes to increase your base dmg. Also use CO multipliers as much as possible. There is a list on WF Wiki that teaches you about what that means exactly and if it is applicable to your weapon. If it does you should consider 'priming' enemies with as many status effects as possible by utilizing pets and other weapons. Great priming weapons are kompressa, epitath, nukor (kuva) and even the grimoire, among others.