Aw, I used that auto-aim exploit to get the revolver
It didn't ensure a kill, but it's difficult to aim and fire with the pistol so when you had zoom hold on and rapidly pressed the zoom button, the aim assist would keep adjusting the crosshairs to an enemy.
By alternating zoom and the fire buttons, it would shoot at the enemy and adjust your aim as he moved. Again, that didn't mean all your shots would hit him or even kill the guy, but it helped make getting the pistol medal a little bit easier.







