Let me preface by saying that I've had my XDs for over a year now and have had zero problems with the standard 5 round magazines. I did pick up two of the 7 round mags as well and almost immediately began having FTF issues with them.(with ball ammo no less) The problems continued and I noticed others reporting similar feeding problems usually with the extended mags. Went to the range today and right away had 2 FTF in back to back extended mags. Just for the hell of it, I removed the grip spacers from the extended mags, reloaded them and went to town. Put 150 rounds through the pair of mags with no further malfunctions. I am going to put some more rounds down range to verify but I am really thinking the feeding issues people are having with those mags are caused by the grip spacers not allowing proper seating of the magazine.