I own a 9mm S&W Performance Center M&P Shield. I routinely use Sig Sauer Elite Performance 115gr for range ammunition and Federal HST 147gr ammunition for self-defense. I have fired approximately 1200 rounds of this ammunition in this gun and have experienced absolutely no issues with ammunition properly feeding into the chamber with either ammunition using the standard S&W magazines. I ordered the MagGuts 2 conversion. I initially installed the MagGuts conversion in a standard 8-round magazine. The MagGuts 2 conversion works great with the Sig Sauer Elite Performance 115gr range ammunition. When I loaded the same converted magazine with the Federal HST ammunition I had more “nose dives” than successful feeds. I uninstalled the MagGuts upgrade from the 8 round magazine and installed in a standard S&W 7 round magazine (assuming further spring compression was needed) and experienced similar poor results. Assuming that although I had carefully followed the installation instructions and watched a half dozen YouTube videos on the installation process I must have installed the Z-spring incorrectly (backwards), I reversed the installation of the Z-spring and reinstalled in the 8-round magazine. I experienced the same results, many (most) “nose dives”. I uninstalled the MagGuts conversion from the 8-round magazine, reverted back to the standard S&W spring configuration and all Federal HST rounds chambered and fired without incident from both the 8 and 7 round magazines. While not my intended use, I will only be using the conversion kit with a magazine I will be using with range ammunition on the range. Lesson learned – don’t assume self-defense ammunition will feed as well as range (FMJ) ammunition with this “upgrade”.
