HISTORY

The M16 was first adopted in 1964 by the United States Air Force (USAF) as the M16. Various modified versions of the M16 design were subsequently fielded under experimental designations, culminating in the M16A1. The M16A1 was simply the M16 with a forward assist as requested by the Army. This weapon remained the primary infantry rifle of the United States military from 1967 until the 1980s, when it was supplemented by the M16A2. The M16A3 is a fully-automatic variant of the M16A2, issued primarily within the United States Naval Special Warfare. The M16A2, in turn, is currently being supplemented by the M16A4, which incorporates the flattop receiver unit developed for the M4 Carbine, and Picatinny rail System. Previous versions of the weapon are still in stock and used primarily by reserve and National Guard units in the United States as well as by the U.S. Air Force.

Naming the M16 Rifle

The M16 was an initial version fielded in the early 1960s; however the U.S. Army began to field the XM16E1 en masse in 1965 with most going to Vietnam. The US Marine Corps also adopted the system during this period. The XM16E1 was standardized as the M16A1 in 1967. A transitional issue was provided to US Army units stationed in Europe. Nearly all US Army units had switched over to the system by the early 1970s. US Army Basic Training units retained the M14 rifle up through 1969. Adoption of the M16A2 by both the US Army and USMC started in the mid 1980s, and the M16A4 began to be fielded even more recently. During the early 1980s a roughly standardized load for this ammunition was adopted throughout NATO

Type Service rifle

Place of origin United States of America

Service history

In service 1961¡§Cpresent

Used by United States of America, at least 73 other users

Wars Vietnam War - Present

Production history

Designed 1957

Produced 1960-present

Number built Over 8 million

Variants See Variants

Specifications

Weight 8.5lbs (3.9kg) loaded

Length 1,006 mm (39.5 in)

Barrel length 508 mm (20 in)

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Cartridge 5.56 x 45 mm NATO, .223 Remington

Caliber 5.56 mm (.223 in)

Action Gas-operated, rotating bolt

Rate of fire 750 to 900 round/min, cyclic

Muzzle velocity 975 m/s (3,200 ft/s), 930 m/s (3,050 ft/s) (see Variants)

Effective range 550 m (600 yd)

Feed system Various STANAG Magazines.

Background

Throughout the 1970s, the Army experimented with various materials to replace brass in cartridge casings. Brass has a number of features that make it almost ideal for a cartridge, including low friction against steel, making it easier to extract, and the ease of which casings can be manufactured. However, brass is also dense and expensive, so replacing it could lower both the cost and weight of the ammunition.

Aluminum and steel were popular materials for complete rounds, and AAI successfully developed a plastic blank. However, none of these materials ever entered production for a variety of reasons. Completely caseless ammunition was also studied on several occasions, notably the German 4.7 mm designs, but issues with reliability and "cook off" were never completely solved.

More recently, the Army started the XM8 system project for a radically improved weapon. However, the program was shelved in favor of an open competition for what became known as OICW Increment 1. (Increment 2 is the stand-alone air bursting grenade launcher known as the XM25, and Increment 3 will be the XM29, a weapon which combines the earlier two increments.) The OICW-1 competition was cancelled on October 31, 2005.