just got my gun not too long a ago and shot 300 rounds thru it no problem. i cleaned it today and put it back together but i hear a click sound whenever i pull the slide back(no mag or ammo), but it only does it the first time and it wont do it again until i dry fire it. is this just the sound of the gun being cocked or could there be something wrong?? its .40 sigma
That's the trigger resetting,you're good.Every time you pull the trigger it gets disconnected from the lockwork so it doesn't go full auto,hence semi-auto,you're cool.Study the working of the gun and you'll "see" it.