Aim for their antlers to prevent them from charging at you, or their blaze canisters to deal with them. When using melee, sneak up to them from tall grasses and go for a stealth kill to not alert the other machines.
Hard outer casing to protect synthetic muscle and operational systems.
Blaze storage canister. Shooting elemental canisters with elemental ammo triggers an explosion that will damage everything nearby. Shoot off this component to collect the resource inside.