Sold Out Quick view Heckler and Koch (HK USA) Heckler and Koch (HK USA) Mr556a4 Upper Kit 5.56mm 11" $2,179.00 Mr556a4 upper kit 5.56mm 11".Caliber: 223 Rem | 5.56 NATOBarrel: 11"Finish: Matte Black Out of Stock Out of Stock
