.....Remove your slide...insert mag.....look thru the NOTCH that the Slide Stop goes thru....If you can see the edge of the mag in that notch, mark the mag....remove the mag.... take a file or dremel tool and grind it down till you cant see the mag anymore.....make sure you DE-BURR the edges after you grind them. After doing this to my Chip mags, I NEVER had another problem with premature slide lock.
In this pic you can see part of the mag in the slide stop NOTCH....
remove slide...
insert EMPTY mag....
if you can see any of the mag INSIDE the NOTCH (only)...mark it with a marker or scribe....
remove mag....
grind/file and de-burr....
insert mag to double check...
repeat till you cant see the mag anymore....
mag on left.....BEFORE
mag on right....AFTER
DO NOT FORGET TO DE-BURR