This piece of the puzzle may have been entered into the thought process somewhere in the last 40 pages, but here is the differences I can tell between my Gen 3 26 (KPDXXX) and my Gen 4 G19 (SASXXX).
My G26 has been flawless with strong positive ejection. It has the 336 ejector and the older extractor with a 3 next to the step.
My G19 has been reliable but with an irregular ejection pattern. To the left, to the left, to the right, to the right, to the front, ..... I think there is a song in there somewhere. Anyways I have video of the spent shell casings bouncing off the front of my slide, my hat and everywhere in between. It has the 30274 ejector and the newer extractor with the 3 on the post.
I have not switched extractors during shooting sessions as I just got the G19 not too long ago. I have swapped them out at my bench. The extractors fall freely out of my G19 but needs the slightest nudge to drop out of my G26.
The newer extractor seems to have more "belly" along the top line. But the biggest difference that I can see is when I push on the front face of the G19 extractor towards the angle (gun assembled, slide closed), I can wiggle the extractor up and down a couple of mils. With the G26 when I push on the extractor the same way I can't seem to detect any movement.
Based on this I would tend to think that either the slide has had too much material relieved or the extractors are slightly too small. I know this has theory has come up in the last several pages and was wondering if anyone else had compared or noticed this?
I am not a gunsmith or claim to be one. I have only had my 2 of 3 Glocks for a couple of years now. If I need to take pictures/vid to better explain, let me know.
Making good people helpless won't make bad people harmless.