I just got a xdm 40 and the same thing is going on here. What is causing the jam is the slide is grabing the round and jamming it into the top of the chamber entrance. The top of the entrance is very sharp and digging into the round. I took a small rat tail file and very carefully took the sharp edge off the top. I went from jamming 1 out of 5 to not jamming again yet. This is stupid on my part and don't try this at home.