M16A3

 M16A3

Caliber: 5.56×45mm M855

The M16A3 is a fully automatic derivative of the M16A2, so its trigger group is the same as that of the M16A1. Other than that, the M16A3 and M16A2 have no differences in appearance. However, in recent years, there has been much confusion about the M16A3, with many people believing it to be a flat-top receiver version of the M16A2. This misconception has been fueled by its appearance in video games and simulation toys. The similarity in appearance between the M16A3 and the M16A2 has led to confusion, compounded by the fact that the M16A3 is primarily used by the Navy for shipboard security and is rarely seen in combat, leading to limited awareness of it. Additionally, Colt once marketed a commercial version of the M16A3 with a flat-top receiver, adding to the confusion.

In the early 1990s, Colt's ACR prototype was initially considered as a candidate for the M16A3. By the mid-1990s, with the cancellation of the ACR program and the military's preference for modifying existing weapons rather than adopting revolutionary new ones, the focus shifted to improving the M16A2. The plan was to retain the basic characteristics of the M16A2 but enhance its accuracy significantly by adopting new optical sights and night vision devices. The original plan was to equip soldiers with the improved rifles within three years (1993-1995). This improvement plan was often mistaken for the M16A3 by outsiders.

M16A2 with Aimpoint Comp scope (US Army designation M68). Since there is no full rail, an adapter is required to install it.

The M16A3 improvement plan was based on a system called "SERFS," which involved adding a set of M1913 standard rails for optional installation of new sights to the M16. Specifically, rails were added above and below the M16, with the top rail extending from the receiver to the front of the barrel. Accessories such as a folding vertical grip or an M203 grenade launcher could be attached to the lower rail, while lasers or optics could be attached to the other rails. The addition of the aluminum "SERFS" system reduced the weight of the M16A3 by 0.23kg compared to the M16A2. However, due to budget constraints, it was estimated that only 3 to 4 M16A3 rifles would be issued per infantry squad. The US Army Ordnance, Ammunition, and Chemical Command reportedly signed a $27.1 million contract with the producers of the M16A2 for the modification of 64,725 rifles.

The M16A3 improvement plan of M16A2 manufacturer FNMI is called "FIRM-M16" (top). The same modification can also be implemented on the M4, called "FIRM-M4" (below). In addition to the scope mount rail, FIRM also has a new flash hider. Since the US military will not be equipped with MIRM-M16, FNMI can only sell "FIRM" accessories directly to users.

However, by the mid-1990s, there was still no official confirmation of the M16A3's formal adoption. Instead, in November 1997, the US Army began the wholesale adoption of the M4/M4A1 carbine, rather than the M16A3 as rumored. The rifles often mistaken for the M16A3 were actually prototypes known as the M16A2E4, which later became the precursor to the M16A4.

Later, some physical pictures of what were believed to be the M16A3 emerged, showing a design vastly different from the early 1990s concept. The only improvement was changing the fixed carrying handle to a flat-top receiver integrated with M1913 rails, making it easier to mount optics. Additionally, it retained the full-automatic capability of the M16A1 while preserving other features of the M16A2. However, this was not the officially adopted M16A3 by the US military but rather a commercial rifle named the M16A3 by Colt, internally designated as the Model 901.

The actual military M16A3 had already been standardized by then. In 1992, the US Navy SEALs were equipped with a batch of M16A2E3 rifles, which were export variants of the M16A2. The only difference from the standard M16A2 was the change to fully automatic capability (as indicated in the military specification MIL-R-71135). Soon after, the US Navy officially designated the M16A2E3 as the M16A3 and issued it to sailors onboard ships and to Naval Construction Battalions ("Seabees"). The current SEABEE Combat Handbook (NAVEDTRA 14234) explicitly mentions the use of the M16A3.

The April 2003 edition of the US Army Field Manual FM23-9 also explicitly states that the M16A3 is a fully automatic version of the M16A2 and does not feature a flat-top receiver. However, the officially standardized M16A3 rifles were produced by FNMI, not Colt (see the attached image). Similarly, this situation occurred with the M16A4 later on. Initially, the M16A2E4 was provided by Colt, but when officially standardized as the M16A4, bulk orders were awarded to FNMI.

The M16A2E3 was produced by Colt, but this was only for export

Due to its limited adoption by the US Navy, the M16A3 was not widely known, and there are few confirmed photographs of it. According to HLTVpro, who served on the CG70 "Lake Erie," he never saw a 3-round burst M16A2 onboard, indicating that the rifles he encountered were fully automatic. Essentially, any M16A2 used onboard ships, if not issued by the Marine Corps, can be assumed to be an M16A3. Initially, I believed that not all M16A3 rifles were produced by FNMI, as @HLTVpro from the TBS Dimension Gate forum (who served in the US Navy) mentioned seeing an M16A3 with a lower receiver from an M16A1 and an upper receiver from an M16A2. However, in April 2020, Larry Vickers mentioned in an advertisement for his book that Colt never produced the M16A3, and all M16A3 rifles used by the US military were ordered from FNMI. Additionally, only a small number were ordered by the Navy.

This photo was first referred to as M16A3 on Colt's official website. Later, Colt's official website was revised and the M16A3 webpage was removed. This picture was directly used in the introduction of M16A4, and it was mentioned that the RAS rail handguard was an optional accessory for the commercial M16A4.

The M16A2E3 produced by Colt was primarily intended for export, such as to the Israel Defense Forces. While Colt's product was essentially the same as FNMI's M16A3, Colt did not receive orders for the US military's "M16A3," and while the SEALs ordered Colt's Model 705, it was referred to as the M16A2E3 at the time, not as the M16A3—naming is crucial for the bureaucratic US Department of Defense.

Due to the confusion surrounding the M16A3 used by the Navy, especially in its early years, many people mistakenly considered Colt's Model 901, featuring a flat-top receiver, to be the standard M16A3. However, according to information provided by Colt's product list, the Model 901 lacks fully automatic capability and is limited to 3-round burst mode. The flat-top receiver, A2 handguard, and 3-round burst are basic characteristics of the pre-1997 M16A2E4 before the addition of the RAS handguard. Colt's commercial version of the M16A3 is essentially a flat-top M16A2, and the designation "A3" is Colt's own, not officially standardized by the military. Therefore, the officially standardized US military M16A3 was produced by FNMI and featured a fixed carrying handle and fully automatic capability.

Interestingly, Colt's website, after a redesign (likely before 2010, the exact time is unclear), directly used the images of the commercial M16A3 in the M16A4's description and stated that users could choose to equip it with a rail system as needed. Perhaps this was done to avoid confusion with the actual military M16A3, but the military-issue M16A4 comes standard with the M5 RAS handguard.

As for the flat-top receiver paired with the M16A2 handguard, known as the "M16A3," it only exists in the world of toy guns. Because in WAR GAMES, burst-only AEGs are at a disadvantage in direct engagements, AEGs in the M16A3 category have always been fully automatic weapons. When manufacturers decided to produce an "M16A3" to make money, they referenced the early "A3" design from Colt's official website.

This is an X-ray of the commercial M16A3.

Fijian soldiers participating in policing operations in Iraq appear to be using Colt's commercial M16A3, but may also be M16A2 export models with flat-top receivers.

Crew members on the USS John C. Stennis CVN74 are practicing shooting with an M16A3. The speed selector markings can be vaguely seen as the four-letter AUTO instead of the five-letter BURST.

The ship is equipped with M16A3 (the markings on the speed machine are unclear, but the possibility of M16A2 is relatively small)

 

SEEBEE IN TRAINING

SEEBEE in Ferauje in 2004

SEEBEE doing shooting practice in Iraq in 2005

The M16A3 that SMGLee has seen, but its upper receiver is flat-top and has a RAS handguard installed. It is likely that someone assembled the upper receiver of the M16A4 and the lower receiver of the M16A3 together.

The A2 handguard rifle in the foreground is probably also an M16A3, but the RAS handguard and flat-top receiver rifles in the distance are not sure whether they use the same burst lower receiver as the one in the picture above, or are they borrowed from the Marine Corps rifles for practice.