0ne Sh0t 0ne Kill is most useful with a gun that reloads frequently and/or quickly such as Pistols and Shotguns manufactured by Jakobs. This pairs well with Decepti0n, as the player can reload in relative safety while moving into position for the shot. Using it along with powerful sniper rifles is also a possibility, since it will allow them to kill many enemies instantly on a critical hit.
This skill paired with Infinity results in a high amount of damage being able to be dealt in a short amount of time. Infinity has only 1 bullet in its magazine at any time, so every bullet fired from Infinity benefits from this skill. The Tw0 Fang skill maximizes the damage dealt in this way.