BRAND NEW- U.S. Manufactured BPP11E Nitrided Riffle Barrel. These are the quick change barrels for the HK21E,HK21EK, HK11E, HK11K, BPP21E, BPP21Ek, BPP11, BPP11K system and factory barrels are getting extremely hard to find. A must have spare part for your HK rifle or Machine gun,