CMMG 55A520BAB: There\'s a world of options when it comes to firearms and calibers, and for those who want to reach out to further targets or hunt with 5.56, the 16-inch Br4 chambered in 5.56x45mm is an awesome choice. Despite all the different caliber offerings in the Dissent lineup, 5.56x45mm still stands as one of the most popular. Equipped with a 16.1\" barrel, this Br4 is one classy carbine. Comes with (2) Magpul 10rd PMAG.