The Packaged – 5.56 16″ M4 Barrel, – Carbine Length comes in our new retail packaging to better gift to others for Holidays, Birthdays, or Other Special Occasions! Also allows dealers to hang our products in store! The 5.56 16″ M4 Barrel, – Carbine Length Packaged is compatible with the AR-15 Platform.The 16″ 5.56 M4 barrel is the perfect barrel to start your next build and add to your AM-15 collection. This barrel is made from 4150 Chrome Moly Vanadium Steel with a Parkerized finish. Featuring a carbine length gas system with a .750″ gas port and a 1:8 twist, this barrel provides top accuracy and precision for your 5.56 build.