The M16 has been the United States military’s main assault rifle since 1963, the current versions in service being the M16A3 and M16A4, with the M16A2 utilized by non-combat personnel. It is an incredibly effective design, inspiring several copies made in other countries like the Canadian C7 or the Chinese CQ.
Attempts have been made repeatedly to replace the M16 with something more modern, such as the Advanced Combat Rifle or the Objective Individual Combat Weapon programs. However, they have consistently failed to find a replacement, aside from the M4 Carbine, a shortened version of the M16 which will eventually replace the majority of the U.S. Army’s M16’s. However, the M4 is also looking to be possibly replaced at the conclusion of the Individual Carbine program in 2013, should a suitable carbine be found.
Since then, another rifle has arisen called the FN SCAR, or SOF (Special Operations Forces) Combat Assault Rife, manufactured by Fabrique Nationale (FN) d’Herstal in Belgium. The SCAR is currently used by a few special police units in Mexico, France and Peru, Biuro Ochrony Rządu or Government Protection Bureau in Poland, and all branches of the United States Special Operations Command, or USSOCOM.
One particularly well-known attempt to replace the M16 was the XM8 assault rifle produced by Heckler & Koch, or H&K, a German weapons manufacturer, which was designed from roughly 2002 to 2005. Many video games made during the time period depict U.S. special forces using the XM8, such as Tom Clancy’s Ghost Recon 2, although the XM8’s futuristic appearance continues to be popular, and features prominently in the upcoming Call of Duty: Black Ops II, which is set in the near-future. The XM8 was comprised of an assault rifle variant, a carbine variant, a squad-automatic-weapon (SAW) variant, and a marksman variant and possessed a relatively unusual appearance, before the program was ended in 2005.
The rifle that stands at the forefront however, is the Heckler & Koch HK416, an assault rifle that was originally intended to do everything the M4 does wrong and then some. Since it’s first use in 2005, the HK416 is now widely-known and continues the high standards set by previous Heckler & Koch rifles, whose weapons are used by the majority of the world’s counter-terrorism forces and SWAT teams. The HK416 is now in service with over 17 countries, including the United States by various special forces units and the Marine Corps. It is also currently involved with the Individual Carbine program, and a variant for both marksmen (HK417) and an automatic rifle variant (M27 Infantry Automatic Rifle) are being produced, the M27 specifically for the Marine Corps.
Some people say the M16 will never be replaced, and while the M16 is a truly exceptional weapon, there are many rifles being produced that show strong possibilities of replacing it and taking up the mantle as the U.S. military’s main assault rifle.