The BCA Andean Bear Complete upper assembly has a 16" Parkerized barrel with a 1:7 twist rate, 15” Light weight Key Mod rail and upper receiver (BCG and charging handle are included). This upper is chambered in 5.56 NATO and machined with M4 feed ramps (both in the receiver and barrel extension) and a A2 flash hider. The BCA Andean Bear Complete upper assembly, like all BCA products, is subjected to numerous QA/QC checks which for our firearms and upper receiver assemblies includes test firing prior to approval and shipment. This rifle is also backed by our BCA limited lifetime warranty. Choose a rifle designed by a U.S. company made in the U.S.A. Choose right, choose accurate, and choose BCA. BCA DOES NOT recommend using steel cased ammo in our Assemblies or Rifles.