New here, have had a FNP 45 for a couple of months now, great gun! I just wanted to say that I had an issue with one of the mags and Bob Ailes with customer service did an excellent job in resolving the issue.
Let me guess on the mag problem... Moving bullets in a full mag? I had this problem in one mag only as well and I am not sure if it matters, but it was the mag that shipped in the gun. I did send out an e-mail with "0" reply so I took on myself to try and fix it, I just removed the spring and gave it a bit of a pull (made it about 1/4" longer) and now noise is gone. The mag works perfectly, but I still make sure it is #3 in my rotation.
No, actually mine would not hold the slide open on the last round. I have seen other posts here with pics about the same problem. I couldn't find anything wrong with it myself. The new mag works fine, I even tried WWB bulk with no problems.