Ok so i just got my first handgun today, the Glock17 gen 5. I have hardly handle any handguns prior to this. I am a noob so im probably making really obvious mistakes. Thast why i need calrifying. With the empty magazine in i go to rack the slide and it stays open. But I cannot push the slide release button after that. IT jsut wont budge at all to release the slide. What am i doing wrong? OR is this a problem with the gun? I simply cannot use the slide release button no matter what once slide is locked back. I have to manually rack the slide again to close it.