My GI Expert has been flawless since I got it over 1500 rounds ago. The factory mags even handle my 200 grain LSWs without any problems.
The gun does shoot low for me so I just compensate by aiming a bit higher. This was tested in a steady rest so I know it's the front sight. May just buy a shorter front sight from Dawson Precision (eventually).
The only problem I have with it is that the bull is shot out of the target after less than one and one half mags.