I've had a search and can't find this in the forums.

Does acquiring a target lock via K4 count as an action? Does it allow EI to trigger another card?

Interested as I'm thinking of Dengar with Unhinged Astromech for the green, K4 for the target lock with EI to trigger Marksmanship (for both shots during the turn if Dengar is defending in arc)

Nope. For a card's effect to be considered an action, it needs to include the word "action" in the text. Since K4 doesn't, it won't trigger Experimental Interface. You can still use Marksmanship with K4, but you'll have to just use your ship's normal action to activate Marksmanship.

The only time you need to use an action to activate a card is if it has the "Action:" header on it.

This is a card that requires an action to be spent:

The are other cards that don't require that you spend your action but their effects grant a free action. A ship with stress wouldn't be able to take advantage of a free action and because it is an action effects that trigger off of performing an action (like Experimental Interface or Push the Limit) will trigger.

This is an example of a card that grants a free action as part of its effect:

K4 Security droid is an example of an effect that neither requires an action to use or counts as an action. You could have a huge stack of stress and K4 Security droid will still let you get your target lock. You couldn't however use that target lock to trigger something like Experimental Interface because the Target Lock was not an action.

The K4 won't trigger Marksmanship but you still have an action to use. Green maneuver, trigger K4 for the free target lock, Focus or Barrel Roll, trigger EI for Marksmanship.

Cool fact, you can also get a lock with k4 if you bump or run into an asteroid as long as you took a green. Since it's not 'action' dependent.

John!