The M16A4 is the fourth generation in the M16 series. This firearm features a muzzle compensator in place of the flash suppressor to manage recoil as well as a heavier and/or a free-floating barrel to increase accuracy. The M16A4 was the standard infantry rifle for the U.S Marine Corps until the M4 carbine replaced it in 2015. It is now used by support and non-infantry Marines.