My new PPQ Q4 is a big disappointment. About every fifth round the slide fails to close completely and, if I pull the trigger, it goes fully forward but is un-cocked and will not fire in spite of a new round being chambered. I have tried bumping the slide forward and the same problem occurs. I am using Magtech ammo but no difference with other brands. Never had this problem with my Glocks and I am wondering if I made a big mistake buying this gun.