I fell for the cheap price and bought 4 boxes of "perfecta" .40 and it feed well when shooting the .40 shield. i loaded up a few mags for my M&P full size and it had alot of fail to feeds, jams,failed to ejects, and was inaccurate. I found that to be odd so i loaded my XDM full size and it had the same problems. I was hoping my older sigma .40 would prove the other 2 pistols were just picky. The exact same problems with the 3rd .40! I usually dont shot off brand ammo and now i remember why i will probably measure OAL and get a grain count or weight when i have time. switched back to federal/winchester the same day and had none of these issues. The Shield still performed well with the perfecta .40 for some reason? just pay the extra money and stay away from cheap ammo!