I broke 750 rounds today. No jams of any kind. I don't think I have it as bad as some. Of course none of the extractor assembly is OEM at this point. It's half aftermarket and half home made. Today I was shooting a handload that's a lighter than my normal one. Brass went mostly high and right with maybe 30% over my head. It all landed 5 to 7 feet away. Nothing to the left or straight back at me. One case hit the top of my head on the way down. I never get hit at all with full power loads.
I did an interesting experiment. I shot ten rounds single feeding. One round in the mag, feed it and shoot. The idea was to take any inconsistency in the position of the next round out of the equation. I then shot a ten round series by loading ten in the mag as one normally would. There was no perceptible difference in the ejection pattern of the two groups. So, at least in my gun, wobbling, jumping, moving, or otherwise unstable next rounds are not a factor.
I have three extractors on order from Glockparts - two OEM and one Lone Wolf Distributers. I plan to experiment with straightening out the angle in the claw and making compensating cuts as needed. I'll need to move the tensioning assembly forward a bit as well. I'm curious to see if that will make a difference, and I don't want to wait for Apex to go into serious production.
If I learn anything significant I'll post results with pics.