ive had 2 case knives and both have had a slight burr on the back side when closed, after the have been open and closed like 50 times. Is this just a normal break in , then they dont develop that burr anymore. to clearify what im talking about is when the knife is closed and you run your finger very lightly over the back side there are slight brass fine burrs. if you wipe them off, and open and close the knife 50 times they come back. Im thinking the knife is tight and it breaks in? Anyone else ever notice this?