The trigger is the only part of the gun that’s moving during the aiming process. If you are having trouble with precision pistol aiming, this video with Brian Zins about “aiming through trigger control” will help.
Trigger finger placement really counts when the shot breaks. Now don’t get me wrong, stance, grip and aiming are important but keep in mind that you can have a perfect grip and hold perfect sight alignment all day long
Video: Precision Pistol Tips Part 3―Brian Zins On The Relationship Between Aiming And Trigger Control
Even if you have a perfect grip and can hold perfect sight alignment all day―it only counts when the gun goes bang after you pull the trigger
Adjust trigger pull weight accurately and easily.