are you sure the threads were wrong on the screw? I had similar issues on with my CMMG 308 LPK. I happened to have a 1/4 28 die so I use it to clean up the threads in my JD Matched Set ($700) and that solved the issue for me. Even threads of the same size can have different tolerances.
Maybe this was my problem:
I don't know... At least you didn't have to work the push pins in and out for hours with a punch just to make it so you could force them in by hand...