In the years that followed the Vietnam War, opportunities for improvement in the M16A1 became evident. The M16A1 lacked sights that were easily adjusted, and while a rugged and lightweight for combat was not a particularly accurate platform. Marine Corps Lieutenant Colonel David Lutz would be the program manager for M16 improvement, and his recommendations and partnership with Colt engineers would lead to the creation of the M16A2. Adopted as standard in 1983 with issue beginning in 1984, the M16A2 would usher in tremendous performance improvement for the M16 family of rifles. By the late 1990s the accuracy of M16A2s would even displace the M14 as the primary National Match competition rifle, a feat that many well-regarded marksmen would have never thought possible considering the rifle’s relatively small .223 caliber.
Lieutenant Colonel David Lutz explains the genesis of the M16A2.
The M16A2 and M40A1 were both far more accurate than their Vietnam era predecessors (Plowman collection).
M16A2 Improvements
- Easily adjustable 1/2 Minute-of-Angle rear sight
- Front sight post upgraded to a square type
- Heavier profile barrel with faster 1-7 twist rate to stabilize heavier bullets (like the 62 grain NATO SS109 / M855 )
- Redesigned, more durable handguards and angled delta ring for easier removal
- Lengthened stock with better grip
- Added brass deflector to prevent hot brass from hitting left handed Marines
- Flash hider redesigned with a closed bottom to reduce muzzle climb and dust signature
- Automatic fire replaced with three round burst feature
Marines firing the M16A2. The M203 grenade launcher, first fielded on the M16A1 in the later years of the Vietnam War, would be attached underneath the M16A2 as shown at right (USMC).
As the USMC was the first branch of the armed forces to adopt the M16A2, serial numbers span from the entirety of the production range. M16A2s have been observed with serials as low as 6 million and as high as well into the 9 million range of Colt production. Some later M16A2s produced by FN were also acquired, and it is possible the Marine Corps also received some Sabre Defense M16A2 replacement receivers. Parts of all varieties were interchangeable, and it didn’t take long for the M16A2 to be widely mixed like most venerable military rifles. Barrels were replaced often, and would come from Colt, FN, and Sabre Defense as well. The overall design would remain unchanged since its inception, and the M16A2 would truly embody the Marine creed of serving in “every clime and place”. From the Caribbean island operations of the 1980s to the Middle Eastern and African operations of the 1990s and early 2000s, the M16A2 would perform very well, giving the Marine riflemen that carried it the ability to engage targets at distances most enemy combatants could not achieve.
USMC FN M16A2 #7299726. This rifle, featured in Marine Corps training manuals, is one of the many M16 platform rifles that would be built for the USMC by FN USA.
Thorough yet easy to comprehend operator’s manuals were issued with the M16A2 (NARA).
USMC M16A2 Rebuilds
M16s of all varieties that were serviced at Marine Corps Logistics Base Albany’s Level 5 rebuild facility were stamped on the right side of the magazine well. The “A” denotes the rebuild having taken place at Albany, and “7 03” standing for date, in this case July 2003. As seen with other weapons, these often indicate a final rebuild before being placed in war reserve storage.
Marines during Operation Desert Shield / Desert Storm with their M16A2s (USMC).
Marines in Mogadishu in 1993 (USMC).
During the peacekeeping missions of the 1990s, a massive technological boom stateside would lead to the M16A2 starting to show its age. Improvements in night vision technology, particularly the ability to pair night vision goggles (NVGs) with infrared aiming devices like the PAQ-4C and later PEQ-2A would make the Picatinny M1913 rail system a necessity. While some M16A2 handguards would be modified to accept added sections of Picatinny rail, these were stop-gap measures and it was clear a more permanent solution was needed. In the summer of 1997 the Marine Corps would adopt the new M16A4 as the standard service rifle. Essentially an M16A2 but equipped with the M5 Picatinny quad rail handguard and “flat top” Picatinny receiver, the M16A4 would allow for a plethora of attachments. The replacement of the M16A2 would be slow however, and not lock into full gear until after the terrorist attacks on 9/11/2001.
The invasion of Iraq in 2003 during Operation Iraqi Freedom would be the last major employment of the M16A2 by the USMC. Images from the invasion show Marine infantrymen using rails added to their M16A2s to mount infrared aiming devices and flashlights, as well as using optics fixed to the top of the M16A2s carry handle. While the M16A2 carry handle did have the ability for mounting optics, the high head position it required made a solid “cheek weld” impossible, reducing accuracy. These problems were alleviated with the newer M16A4, but its presence was limited in the earliest years of the GWOT. which would begin filtering in to Marine Corps infantry battalions in late 2003.
Scoped USMC M16A2 Rifles
Over the course of the M16A2’s service life, various scopes were added to the carry handle for special purpose and designated marksman roles. The most common examples are the Colt 4×20 M16A1/A2 specific carry handle scope, and during the early days of the GWOT the Trijicon Advanced Combat Optical Gunsight, or “ACOG” as it is known to the Marine Corps. Other less common variants, such as Burris, Lyman or Redfield scopes have been observed. Some scoped M16A2s have been observed with cheek risers added to the stock as well.
Marine infantrymen with ACOG scoped M16A2s during the OIF II in 2004. M16A4s with ACOGs can be seen in the background, as M16A2s had become less common by this point (USMC).
The USMC M16A2 as a Training & Support Rifle
Generations of Marines would learn the basics of marksmanship with the M16A2, a role it would continue in past its retirement from frontline units. A service rifle that was suited for the “across-the-course” firing line, Marine recruits would qualify with the M16A2 at Camp Pendleton, California and Parris Island, South Carolina from 1983 until 2010.
Before practicing “full course” for rifle qualification, Battlesight Zero (BZO) would be determined on 25 meter targets.
From left: Marines in the Standing, Kneeling, Sitting and Prone positions during Rifle Qualification (USMC).
The Table 1 Course of Fire was the practice and qualification course for the Marines until 2021, when it was replaced with the Annual Rifle Qualification (ARQ). Table 1 was a modified version of the National Match “Across-the-Course” course of fire, and would be fired with M4s and M16A4s with Trijicon RCOs from 2010 to 2021.
Left: the Author learning the basics of Marine Corps marksmanship with an M16A2 (USMC).
Right: the Table 1 Course of Fire utilized the Able, Dog, and B Mod Targets.
The M16A2 would end its service with the USMC Rifle Team and training Marine recruits, officially being retired from this role in 2010 (USMC).