My Orginal Handguards for my Preban Norinco Type-56S-1 became brittle or Rought feeling after I put over 500 Rounds throught it. I have one of the C.S.I. Norinco's with the Norinco Banner, and marked like a Chicom Type-56-1 with the 66 in Triangle, and Proper Marking's execpt for the S. Execpt for putting the Wide Norinco Checkered Grip and a Bulgarian Guiderod Spring Assy. on it. it is all orginal. Is it normal for the standard Chinese Chu Wood light Beige or Tan Colored Wood(Chinese Military Wood) to become rought like that. I dont recall my Polytech Wood doing after fireing. I had my Gunsmith refinish them, to like new condition, but now they are getting rought again. Is this the nature of Norinco Wood.