How to Kill an Automaton in D&D

Mud prostrates himself in the church any praise doesn't you mud yeah I probably have some sort of deity that my drew it a magic comes from. The shot deals 46 bludgeoning damage and 46 fire damage if it hits the creature plus make a DC 16 strength saving throw this thing is gonna blow up in my face so I'm gonna do 40 d6 one two three four this is for bludgeoning that's a lot of dice Kybor is basically throwing a grenade at me right now 17 and 18  this is for heat metal, we never use cover mechanics but yeah you absolutely can do that there is a system for that in D&D then I'm doing that