Help me diagnose and cure this malfunction!

[teamacacia]

Background: I am the only owner of this 9mm M&P. Have never experienced this malfunction with the original two magazines. Recently purchased 10 S&W manufactured 9mm mags online (from reputable site) and have since experienced this malfunction the past two times I have gone out and really tried to push the gun hard...i.e. not just shooting for target practice. During the first training session, this malfunction only appeared during reloads but today appeard during a reload and then again mid-magazine. I have marked mags and kept running them throughout the morning but failed to repeat the failures again. My first though is weak mag springs but I'm not sure. I aprreciate the help.

EDIT: The new mags are of the "old design" in that they have the circle on the bottom and not the rectangle/square button to disassemble the mag.

[ToddG]

80% likelihood it's weak magazine springs.

[teamacacia]

80% likelihood it's weak magazine springs.

Todd, thanks. What are the recommended replacement spring? Wolf power springs or OEM parts? Also, if it is not a weak mag spring, what would you consider to be the most likely culprit? I had considered releasing the slide lock ever so slightly too soon for the reload but not sure with the mid-mag malfunction.