I am aware of this question regarding feats that can be used when firing a ranged siege engine and this question regarding whether Vital Strike can be used when firing slow-firing weapons. The answers to the first question do not discuss Vital Strike, while it is unclear whether the answers to the second question apply. I believe that the essence of this question boils down to:

  • Is firing a light ballista an Attack action?
  • Is there any other reason that a character firing a light ballista cannot use this feat to turn base damage of 3d8 into 6d8?

Regarding the first sub-question, I found it difficult to find any clear statements regarding what type of action is required to fire a siege engine. The best indication I could find was in an example on page 19 of the Players Guide to the Skull and Shackles Adventure Path (emphasis mine):

...If the same light catapult were instead crewed by three creatures, two could spend full-round actions aiming it and the remaining creature could fire it with a standard action.

If anyone is interested in the context, the character hoping to use the feat is an 8th level ranger with the Siege Engineer and Deadly Aim feats, employed as light ballista gunner on a pirate vessel. (I am already aware from the answers to this question that Deadly Aim and Vital Strike can be used in combination.)


1 Answer 1


Yes, you can

Vital Strike requires you to use the Attack action, which is a type of standard action.

Vital Strike

When you use the attack action, you can make one attack at your highest base attack bonus that deals additional damage.


Making an attack is a standard action.

While aiming and reloading siege weapons are normally full-round actions, firing one is usually a standard action (unless otherwise noted), like attacking with any other weapon. Thought this isn't explicitly called out in their rules ("firing a siege weapon uses a standard/full-round action"), it is assumed to work just like firing any other ranged weapon due to the wording used when describing their mechanics, and because nothing says otherwise.

Proficiency: Siege engines are exotic weapons.

Ranged Attacks: Unlike normal ranged weapons, siege engines do not deal half damage when attacking objects.

Critical Hits: When a direct-fire siege engine or a close assault siege engine scores a critical hit, it confirms the critical and deals critical hit damage just like any other weapon. If an indirect-fire ranged siege engine rolls a natural 20 on its targeting check, it can also score a critical hit.

Direct-Fire Ranged Siege Engines: Direct-fire weapons launch their projectiles on a relatively flat trajectory, allowing them to more easily target creatures or pummel barriers directly in front of them. A direct-fire weapon uses a normal attack roll, with the normal penalty for nonproficient use.

While there are siege weapons that have specific mechanics to operating and firing them, a Ballista is described as essentially a Huge crossbow fixed in place:

Ballista: A ballista is essentially a Huge heavy crossbow fixed in place. Its size makes it hard for most creatures to aim it. Thus, a Medium creature takes a –4 penalty on attack rolls when using a ballista, and a Small creature takes a –6 penalty. It takes a creature smaller than Large two full-round actions to reload the ballista after firing.

  • \$\begingroup\$ @ShadowKras I need coffee... I forgot to filter for 5E. I will go back to sleep now. \$\endgroup\$
    – Slagmoth
    May 21, 2019 at 13:24
  • \$\begingroup\$ I'm unsure that this substantiates that the person performing the Siege Weapon "fire" standard action is performing an attack standard action, not pulling a lever as a standard action. I think any true correct answer has to address this because of the FAQ on Vital Strike. \$\endgroup\$
    – Ifusaso
    May 21, 2019 at 16:43
  • \$\begingroup\$ @Ifusaso There are siege weapons without any levers. There is not a single mention of what action is used to activate a siege weapon, but there are mentions everywhere that they are similar to weapons. \$\endgroup\$
    – ShadowKras
    May 21, 2019 at 16:48
  • \$\begingroup\$ We know you can use vital strike with ranged weapons, and a light ballista is described as a Huge crossbow. \$\endgroup\$
    – ShadowKras
    May 21, 2019 at 16:49
  • \$\begingroup\$ That seems solid. \$\endgroup\$
    – Ifusaso
    May 21, 2019 at 17:26

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