In D&D 5e, can a 5th-level fighter shoot a hand crossbow 4 times per turn using the Crossbow Expert feat?
The fighter’s Extra Attack feature says (PHB, p. 72):
Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.
The Crossbow Expert feat says (PHB, p. 165):
- You ignore the loading quality of crossbows with which you are proficient.
- When you use the Attack action and attack with a one-handed weapon, you can use a bonus action to attack with a loaded hand crossbow you are holding.
Is the following statement valid?
The fighter is holding a hand crossbow. He begins his turn. He takes an Attack action; using his Extra Attack feature along with the first benefit of Crossbow Expert, he shoots twice during this action. Then he takes a bonus action. Using the last benefit of Crossbow Expert, he makes this an Attack action. He is limited to using a hand crossbow during this action. He shoots twice using his Extra Attack feature. (Assume he can do this with the same hand crossbow.)
It is ambiguous whether “you can use a bonus action to attack” means “you can use a bonus action to take exactly one shot” or “you can use your bonus action for the round as an Attack action”. Or even if it does mean “you can use a bonus action to take one shot”, it is ambiguous whether it means “an Attack action in which you use a one-handed weapon gives you an opportunity to shoot during your bonus action” or “a one-handed weapon attack made during an Attack action gives you an opportunity to shoot during your bonus action”. (One bonus shot per Attack action, or one bonus shot per attack within the Attack action?)
Your first ambiguity isn’t really ambiguous at all. The distinction between an Attack action and an attack is pretty clear. Heck, both of the quotes in your question make that distinction.
For reference, the Attack action is defined as:
The most common action to take in combat is the Attack action, whether you are swinging a sword, firing an arrow from a bow, or brawling with your fists.
With this action, you make one melee or ranged attack. See the “Making an Attack” section for the rules that govern attacks.
Certain features, such as the Extra Attack feature of the fighter, allow you to make more than one attack with this action.
Just like the quotes in your question, it refers to the Attack action and an attack as two entirely separate things. So “you can use a bonus action to attack” means that you can use a bonus action to make one attack, not to take the Attack action.
Your second ambiguity is ambiguous; it could mean that each attack with a one-handed weapon allows you to use a bonus action to attack or that the Attack action as a whole does. Fortunately, it doesn’t really matter, because:
You can take only one bonus action on your turn, so you must choose which bonus action to use when you have more than one available.
So even if every attack you make with a one-handed weapon allows you to make an attack as a bonus action, you can still only take one bonus action and make one attack.
To address your comment, we have the preceding text from the definition of bonus actions:
You can take a bonus action only when a special ability, spell, or other feature of the game states that you can do something as a bonus action. You otherwise don’t have a bonus action to take.
You don’t have a bonus action that Crossbow Expert allows you to make attacks with. Crossbow Expert gives you a bonus action consisting of a single attack. Even if it gives you that bonus action twice, (or up to 4 times for high level Fighters), you can still only take it once.