I had the same issue with the PMC ammo over the last 2 days. Bad thing is it happened during the my CPL range time. Good thing is both instructers fired it and had the same issues. I had one mag were it FTF each round!!!. I guess we all know PMC is not a good ammo for the SD40. I think I will send it back to S&W since they seem to modify the feeder and I shouldn't have an issue with any ammo.