Assault Concussion Missiles

Assault Concussion Missiles deals 1 damage to each adjacent hull zone of the defending hull zone. This damage is first applied to any shields in those zones. If there are no shields, then the damage would be applied as facedown damage cards unless additional card effects allow for them to be applied faceup.

Reference

The damage caused by this card cannot be reduced by the defense token.

Assault Concussion Missiles cannot be resolved if the ship it is equipped too has the faceup damage card Targeter Disruption.

A defending ship that spends a contain defense token and also has Damage Control Officer equipped (and not discarded) will prevent any critical effects from resolving.

A defending ship that has Commander Gherant equipped (and not discarded), the attacker cannot resolve any critical effects.

How does ACM and XI7 interact?
Due to the timing and wording of these cards, when ACM resolves, it deals 1 damage to adjacent hull zones, for a total of 2 damage. XI7 doesn’t allow “more than 1 damage on hull zones other than the defending hull zone.” when a Redirect is spent. This is further reinforced in the XI7 FAQ.

“XI7 Turbolasers prevents the defender from suffering more than one damage in total on hull zones other than the defending hull zone.”

Thus if the Defender “spends” a Redirect, and the attacker chooses to resolve ACM, ACM would only be able to deal “1” damage, as the 2nd damage is prevented from being applied.
The defender is unable to redirect any other damage away from the defending hull zone due to the ACM damage.

The defender applies damages, and would be able to choose which adjacent hull zone suffers the 1 damage from ACM.