The set trigger can be adjusted by turning the screw located in front of the trigger no need to disassemble. My magazine drops clear as soon as I press the release so maybe the one ya used was a non genuine magazine??
I like a heavier trigger so the normal trigger suits me
To be honest I've never tried to drop a round in it from the top I always feedem from the magazine but will try when I get a chance and let ya know how it goes