I'm doing a drill now that has me aim gun and when beep sounds pull trigger as fast as I can and watch for sight movement. I still get some movement from time to time and I believe it has to do with "milking" the gun or when you move your trigger finger, the whole hand flexes just enough to cause sight movement. Anyone have a different drill that worked for them to separate trigger finger movement from twitching hand? My grip is good. I feel it has a little to do with hand tension, but it's not always consistent.
EDIT: when I do my drill above, I do NOT rest finger on trigger, rather it is off the trigger to simulate real life fast shooting.