BRAND NEW- U.S. Manufactured BPP23E Nitrided Riffle Barrel. This are the quick change barrels for the HK23E,HK23EK, HK13, HK13K, BPP23E, BPP23Ek, BPP13, BPP13K system and factory barrels are getting extremely hard to find. A must have spare part for your HK rifle or Machine gun,