It increases the damage done with alien weapons by 20%.
To get this perk, the player character must find a "shooting range" in the weapons lab (a room with an alien atomizer and an alien disintegrator next to a switch). The ranges are in approximately the center of the map north-to-south, and on the eastern side. Activating the switch closest to the door summons brahmin, while activating the far switch teleports enemies abducted by the aliens to a second range.
In order to get the perk, ten enemies must be killed with alien weapons consecutively. There are four types of enemies at the shooting range:
Additionally, the player does not have to kill any enemies. Rather, spawning them through the button and letting them kill each other is enough for the perk to be obtained. Having a guardian drone with the player at the shooting range may interfere with obtaining this perk.
Not that many ranged enemies will choose the player as a target over their fellow captives.
It is possible to enter the right, brahmin only range, but a wall and low ceiling ducting prevent access to the left combat range, meaning that bodies of enemies killed there cannot be looted.
It is possible for the perk not to trigger, even after several switch activations. To remedy this, simply save and then load the save. After loading, activate the switch again and the perk should unlock. [verified]