I just received my new Zero Tolerance 560 today. After a short test drive, I noticed the lockup seemed a bit odd. It appears that the frame lock wants to grind against the tang, when you put a firm grip on the knife. The frame lock wants to travel inward on the tang and then it gets stuck. It literally grinds to a halt. Has anyone else noticed this??? It seems like the milling is of just enough to make this a problem. Overall I like the knife, however, this appears to be a big flaw. I know it's not a Hinderer, however I expected much more. Thanks in advance for your feedback.