This is just to throw it out there, on one of my 80% Glocks I built I had a problem with putting a spring in, in the wrong order, and that caused it to not run correctly on ejection. My son-in-law, a Glock armorer, looked at it and figured it out right away and I'd been fighting it not locking back or something like that as it has been too long to remember exactly. If it is an 80% you built let me know and I'll take a look and figure which spring and order was wrong.

Sounds to me you have a cycling problem from limp rist or something mechanical, not the load.

But on the load, did you run them through a 9mm check gauge?