I was wondering about some magazines I have. When I shoot my 15 rd mags everything works fine, but when I shoot my 10 rd mag the slide doesn't stay locked after the last round. Why?
Try to change the magazine spring. Perhaps its not stiff enough to push the slide release after the last round.
I got rid of both of my 10rnd mags. They had the same issue, then I put new springs in and they worked too well or something because after round 1 they would jam every time. Different ammo, different glocks, always a jam.