Hi, I guess the good way would be to use the new conditional_button_device.IsHoldingItem(Agent:agent, KeyItemIndex:int) on the elimination_result.EliminatingCharacter of any EliminatedEvent (team_settings_and_inventory_device, elimination_manager_device, fort_character).
You’ll have to make many conditional button devices and it won’t work for explosives since they’re not hitscan.
What you could do also is to detect classes Attribute Evaluator not working when attempting to find player's class - #2 by wasti, but it would be more of a gungame thing than a weapon upgrade thing, if that makes sense.
These are just ideas, I’ve never actually done that.