I mentioned a while back how I had swapped out the connector in my Gen 4 Glock 21 for a new factory minus connector. It actually didn't do much to improve the trigger pull, and after a practice session last night I decided to haul the Gen 3 "-" connector out of my G34 and stick it in my 21. I changed no other internal parts.
Prior to changing the connectors, the trigger pull on my G21 measured an average 4.5 lbs. After installing the Gen 3 connector, it measured an average of 4 lbs. Visually the connectors appeared the same before I swapped them out, but clearly there's something different about the Gen 3 connector. My best theory is because the Gen 3 connector has had 10k+ rounds on it and about a hojillion dry fires, it's cleaned up a bit and has better contact surfaces than the Gen 4 connector.