Recently aquired a new pf9 and took it to the range. Fired 50 rounds of armscorr through it and it ran fine and then switched to Remington pmc for 50 rounds and had a few double feeds and gun stopped holding open after last round about halfway through the box. I field stripped the gun and reassembled and didn't see anything wrong with the slide catch or magazine follower and it held open when I pulled the slide to the rear but not when firing last round of the magazine? Anyone have any suggestions on what the issue might be. I am hoping maybe it just didn't like the Remington ammo, but haven't had a chance to get to the range again yet to try anything different.