I need some help with the PSI Bolt Action 30 cal bullet pen. It says in the instructions to make sure the bolt action on the cap is tight and there's a very small screw inside the cap that you're supposed to tighten. I've tightened the screw to the point that if I tighten it anymore I might snap the screw head off. This is my first one of these and when I put the parts together in my hand it seems the spring has enough tension on the bolt to keep it tight. How tight do I need to get this screw? Is this screw just there to allow for a right hand vs. left hand user so that you can turn the clip by loosening it? Thanks for any help offered.