Use the Hidden Gun Ability 3 times against your Target as The Corsair in a single session of Capture The Artifact.The Corsair is the female pirate character. On the Selection screen she is the 3rd character down on the left side.
You will need to be at least level 17 before you can earn this achievement, as you wont be able to purchase the "Hidden Gun" ability before then. If you're not yet level 17 then I recommend starting with The Vulture achievement which has no level restrictions:
or the Pirate's Bravery Achievement which can be earned at level 15:
I don't know how familiar you are with the multiplayer modes so I'm just going going to assume you know very little and cover all the important information, feel free to skip any part of this that you don't need.
Setting up your abilitiesIn the Multiplayer main menu you'll want to push LB on your controller then select "Abilities Sets". After that you'll want to buy (with Abstergo Points) or select any of the non-default sets.
Select "Ability 1" or "Ability 2" depending on if you want to assign the "Hidden Gun" ability to the LB or RB button respectively. Once you selected which ability you want to assign it to you can buy the Hidden Gun ability for 50 Abstergo points.
If you have Abstergo points to spare I recommend adding at very least the faster cool-down perk as this will help you earn this as well as the other DLC achievements faster.
Make sure you select this ability set when entering a multiplayer match, if you forget you'll have the option to change it whenever you die by using the D-Pad and A-button.
Setting up the gameFrom the Multiplayer main menu select Custom Match (private matches work too) set it to "Free-For-All" mode then "Capture the Artifact". Once you've found a game try to select the Corsair as your character.
Using the AbilityFist you'll need to lock on to your target using the Left Trigger. Once you've got a lock you'll wan to push and hold the button you assigned. You'll have to hold the button for a few seconds while your character lines up the shot, once the artifacting becomes a single solid line pointed at your target you can release the button to fire the shot.
Keep in mind that the shot will only count if it actually hits your target and your target was actually your opponent. Civilians and obstacles can sometimes obstruct your shot.
Once you use it you will need to wait for the ability to cool-down before you can use it again, Since the 3 uses have to be in the same session try to get them done quickly so you don't run out of time.
A lot of other players don't like people who use the hidden gun as they feel it is an unbalanced weapon, keep this in mind as you might receive flack for using it.
StrategyIn capture the artifact one player will be an artifact carrier and the other players will attempt to kill the carrier and steal the artifact. I found that most games there tends to be a lot of running which can make it easier to identify the artifact carrier (this is the person you want to target).
Typically confronting targets from the ground is difficult as it's much easier for the target to notice you and run to a location where you cannot make the shot or stun you before you're able. This becomes even more difficult since it takes so long to line up the shot.
I recommend climbing to a roof top in a central area and waiting for the game to identify a running artifact carrier for you. Quickly lock on and start charging up your hidden gun. Locking on can sometimes be a challenge at such a long distance but you'll have an easier time lining up and firing your shot from a high vantage point.
Wait for your ability to cool down and repeat the process 2 more times. The achievement should pop after your 3rd successful kill.
I welcome any other tips or strategies for earning this achievement. Thanks for reading!