learn your targets playstyle, he has a job and he does it well learn how to be X hero's counter.
Utilise his melee by swinging your cross hair side to side as the animation creates damage in its view. By binding melee to right click and leap to middle mouse button, your leap into melee combo becomes a breeze!. While primary fire is active a tap onto melee creates an animation cancel that allows a cross hair swing for multiple hits with a melee and since you never held off of the primary fire you return to an extended clip size as your melee aoe created about 40 ammo time for aprox 60% of damage and when timed with evasive manoeuvres it can extend both your dps capabilities and multi kill potential when faced with many low hp targets with little time to react.