【CUSTOM GBB WORKSHOP】 COLT XM16E1 model 603 WE GBB base deep marking, deep 0.3mm Steel out barrel ra tech teel bolt ra tech Magnetic Locking NPAS plastic loading nozzle ra tech fire trigger box ra tech steel select real magazine release real takedown pins real ejection port cover real forward assist real barrel nut assembly real crush washer real charging handle real rear sight real front swivel real trigger guard real handguard retainer real handguard real grip real stock Anodizing phosphate coating detail fix