Hi I am a novice ak 47 owner. I have a century arms wasr 10. The rifle shoots great and did not appear to have any of the various issues that I have heard about with century arms rifles. When I first bought it I took it apart for cleaning and inspection and everything looked fine, After having fired 100 rounds through it I decided to clean it and see how everything look. I have notice to small marks on the bottom of the gas piston that I do not believe where there when I first cleaned after purchase. Can anyone tell me what they are, are they something I have to worry about. Thanks for any help!!