This is my first post here and I hope I found the right place to work out a truly frustrating problem.
Background: I have been shooting Glock's for 15 years off and on and carrying one for better then 6 years. CCW, practical pistol, IDPA, etc. I currently shoot Glock models 22gen1, 23 gen4, 19gen4, 34gen4, 35gen3. I am right handed, right eye dominant and use a thumbs forward grip. I keep both eyes open using a isosceles stance.
Problem: Every Glock I own shoots left of point of aim. The amount varies by model and range but it's safe to say 4-6" @ 15 yards or so. For years I ha e drifted the rear sight to the right to correct for this. For years I thought this was mostly normal. Some recent drills I started doing really questioned that logic. Particularly shooting on handed strong side only, weak side only shooting. I found my point of impact was right in both instances. This got the gears turning, shooting two handed from some form of rest also brought things back towards normal.
What I have tried: When you drop "glock shoots left" into the Internet the results make your head hurt. I have tried several things trying to work out some improvements. I have tried changing the location of my finger on the trigger, exaggerating grip changes, dry firing, dry firing and dry firing. I have been unable to diagnose what in particular is causing the problem. Worse yet I am consistently screwed up across all the guns. This leads me to believe the problem is absolutely me.
A couple of things I have observed in trying to diagnose this problem.
1. Strong hand only shoots mostly POA / POI.
2. Shooting from a rested position two handed shoots POA/POI. Such as resting on a fence post, hood, etc.
3. Slow fire vs. Rapid fire doesn't seem to change thing's. Perhaps slow is actually slightly worse.
4. The weakest portion of my grip is my week / support hand. I feel like recoil breaks my grip and I find myself readjusting throughout shooting.
I know this isn't something that is going to change overnight. I desperately need some direction on how to get out of this hole. I am willing to put in the work, time, ammo, training and money I just don't know where to start.
I have some links to photos of targets but need some more posts before I can add them
Thanks