Can my 2019 UA Artificer hit 4 times in a turn by combining the Arcane Armament feature with the Dual Wielder feat?

Question

I'm having an argument with the DM as usual. My UA Artificer (2019) reached level 8, and I have a new set of goodies. I want to dual-wield maces.

Looking at the Arcane Armament feature I received at level 5:

Starting at 5th level, you can attack twice, rather than once, whenever you take the Attack action on your turn, but one of the attacks must be made with a magic weapon, the magic of which you use to propel the attack.

Using the Dual Wielder feat (PHB, p. 165), I can use Two-Weapon Fighting (PHB, p. 195) to dual-wield my maces:

When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a bonus action to attack with a different light melee weapon that you’re holding in the other hand. You don’t add your ability modifier to the damage of the bonus attack, unless that modifier is negative.

The description of the Radiant Weapon infusion says:

This magic weapon grants a +1 bonus to attack and damage rolls made with it. While holding it, the wielder can take a bonus action to cause it to shed bright light in a 30-foot radius and dim light for an additional 30 feet. The wielder can extinguish the light as a bonus action.

As a reaction immediately after being hit by a melee attack, the wielder can cause the attacker to be blinded until the end of the attacker’s next turn, unless the attacker succeeds on a Constitution saving throw against your spell save DC. Once used, this reaction can’t be used again until the wielder finishes a short or long rest.

The new arcane weapon artificer spell description says:

You channel arcane energy into one simple or martial weapon you’re holding, and choose one damage type: acid, cold, fire, lightning, poison, or thunder. Until the spell ends, you deal an extra 1d6 damage of the chosen type to any target you hit with the weapon. If the weapon isn’t magical, it becomes a magic weapon for the spell’s duration.

As a bonus action, you can change the damage type, choosing from the options above.

If I were to use my Radiant Weapon infusion on one weapon, and the arcane weapon spell on the other, would I benefit from Arcane Armament twice on my turn, equaling 4 attacks?

The DM is stating that Arcane Armament is only triggered once: only the Mace in the primary hand causes it, and the other mace (regardless of being magical) does not count, as it is a bonus action - totaling 3 hits, not 4. Is this true, as I see it being triggered once per use of a magic weapon?

Answer 1

A couple things limit you to 3 attacks

There are a few subtleties in the rules that you have missed that prevent you from getting a 4th attack. First of all, as explained in the rule you quoted, two-weapon fighting requires you to use your bonus action, and you only have one bonus action per turn, so you can only gain at most one additional attack with two-weapon fighting. Second, you also only have one Action per turn. Arcane Armament allows you to make a 2nd attack with that action, but you are still only taking the Attack action once per turn, so there is only one opportunity for two-weapon fighting to trigger.

So, to take you through the sequence of events that gives you 3 attacks, assuming you take the Dual Wielder feat: first, you take the Attack action. Because you are attacking with a magic weapon, you can make 2 attacks. Both of your weapons are magical, so it doesn't matter which weapons you attack with: you can attack twice with the same weapon, or once with each. After either one of these attacks, you can use two-weapon fighting to attack with the other weapon, using your bonus action in the process. Ultimately, this gives you 3 attacks, provided that at least one attack uses each weapon. And one of those attacks will not add your ability modifier to the damage. Generally, you would want to make your 2 attacks using the mace with Arcane Weapon cast on it so you have an additional chance to deal the elemental damage, and 1 attack with the other mace.

Dual Wielder is probably counter-productive for an artificer anyway

Unless you chose Archivist as your artificer specialization, you already have a way to deal damage as a bonus action that deals more damage than your 3rd mace attack would, by commanding your companion or turret to make an attack. So taking the Dual Wielder feat and fighting with 2 maces will most likely decrease your damage output. It also reduces your potential AC by 1, since you give up the option of a shield in order wield 2 weapons. Lastly, taking the feat means you miss out on an ability score improvement, which is a big deal for an artificer who needs high scores in both strength and intelligence, and probably also constitution if you're fighting in melee. (Exception for Battle Smith, which gets to use their intelligence modifier for magic weapon attacks.)

Answer 2

You'll only get Arcane Armament's benefit once per Attack action

Arcane Armament says that you get to attack twice when you use the Attack action. It then has some limitations in that you have to use at least 1 magic weapon. That doesn't mean you get an extra attack per magic weapon, just that you have to use one or you don't get ANY extra attacks. Note the difference between (capital A) Attack action and a (lowercase a) attack as explained in this question.

Two-Weapon Fighting gives you an extra attack (by using a bonus action), but it doesn't give you an extra Attack action. (Very few things actually give another Attack action, a Fighter's Action Surge being one of the common ones).

So it goes like this:

• You use an Attack action (using up your only action for the turn), getting one attack.
• Arcane Armament applies, giving you another attack (one of these has to be with a magic weapon)
• Two-Weapon Fighting applies, giving you another attack (at the cost of a bonus action)

3 attacks.

Answer 3

Arcane Armament procs off the Attack Action.

The additional attack from two-weapon fighting is a bonus action. (The Dual Wielder feat does nothing for your case except let you dual-wield maces.)

A bonus action and the Attack action are not interchangeable, even if the bonus action in question is an attack. It's still a bonus action, and the Attack action can never be a bonus action.