Colt M-16

This relatively lightweight rifle has a 5.56 mm caliber, air-cooled, gas-operated, magazine-fed rifle. It has a rotary bolt, which is activated by direct impingement gas operation.

The design of the gun is based on ArmaLite AR-15, which was developed further by Colt. Ever since 1967 it has been the main assault rifle of the United States army, firing the NATO standard 5.56 mm ammunition.

The M16 series has three models - the first to be designed are the M16 and M16A1 models, the second was the M16A2, which was used in the 1980s, and third version is the M16A4, which has became the standard for the United States Marine Corps. The M16A4 was first during Operation Iraqi Freedom, replacing the M16A2.

The M16 was the result of studies carried out after the World War II, to find an efficient weapon for the needs of a modern battle. After studying extensive battlefield reports it was concluded that combat took place at short ranges, and most of the time fighting armies ran into each other by surprise. In such tense and close situations taking an accurate aim and shooting was difficult, as the target tended to move around. It was noticed that the army with the most firepower, and which could be shot at random, had a larger chance of victory.

To understand more the United States Armed Forces carried out the "Project SALVO". This ran in two phases and it eventually led to the development of a weapon that could fire four rounds into a 20-inch (0.5 m) area, with greater efficiency than the existing semi-automatic weapons.

More weapons were tested, among them was the T44, which was later named the M14 and chosen as the new battle rifle for the U.S. Army. However around the same time the ArmaLite developed the AR-10, which was better designed, lighter and with greater recoil control. This gun was further improved and tested later as AR-15.

After viewing a demonstration of the AR-15 in July 1960, over 8000 rifles were ordered at Strategic Air Command airbases. The Advanced Research Projects Agency or ARPA also bought 1,000 rifles for their South Vietnamese troops, in 1962. The field reports were very favorable.

In the mean time doubts were raised about the choice of M14s and its production was halted. The U.S Army and the Air force then ordered XM16E1s and other smaller guns were experimented with. In a Small Arms Weapons Systems project, these guns were recommended, and now it was referred to as the M16.

The M14s was difficult to use in the Vietnam War in 1965. It had a host of problems, and most important it was unwieldy to use in the very different jungle warfare, of Vietnam, which often took place at very close range. Adding to the woes, fully automatic weapons at that time had considerable recoil, and so these were delivered in semi-automatic mode, which proved to be a hindrance.

To give its troops more efficient firepower, the XM16E1 was introduced. As a prototype the army-version of XM16E1, was practically the same weapon as the M16, it was fitted with a forward assist, but it too did not live up to its promise. Improvements were carried out, and new M16A1 were sent to the troops, however rifles also encountered problems on the battlefield. These needed required regular cleaning and lubrication for reliability, but the soldiers were not given cleaning equipment, nor, were they adequately trained to use these rifles. Soon these problems were overcome, and adequate instructions on rifle maintenance were sent to the soldiers, this added to its effectiveness.

In The M16A1 final production model the "bird-cage" flash suppressor replaced the earlier three-pronged flash suppressor this meant that twigs and leaves did not get into the rifle. Many other improvements, included fully chromed bores were introduced. Other malfunctions, which occurred because of fouling and corrosion, were also taken care off. For added safety a rib was built into the side of the receiver. This made sure that the magazine was never released unintentionally. Also improvements were made to prevent the bolt from being inserted upside down

Over time M16 has become a reliable weapon system. There are now many versions AR-15/M16 design, with different manufactures and assemblers. Some of the main companies manufacturing these are Armalite, Barrett, Bushmaster, Colt, Continental Machine Tool, Diemaco DPMS, Fabrique Nationale, Les Baer Custom, Lewis Machine & Tool, Olympic Arms, Rock River Arms, Wilson Combat and more. Civilians use the semi-automatic versions, or 'AR-15s', and it has many other versions. With tremendous after market support, this weapon will be around for a while.

The M16 remains the most commonly manufactured 5.56 x 45 mm rifle in the world. These have replaced M14 and M1 Carbine series as standard infantry rifles. It has been used as a sniper and designated marksman rifle.

The modifications to the M16A2 made it into a more sophisticated weapon. Among other improvements in design the action was also improved, with a three-round burst setting.

The M16A3 a fully automatic version of the M16A2, was adopted primarily by for the Navy SEALs. This has a Safe-Semi-Auto trigger group, similar to the M16A1.

The M16A4, which is the most sophisticated weapons as of yet, can also be equipped with a carry handle and sighting systems. This is very much in tune with the modern needs.

The development of the Colt M16 series of rifles is story of technological advancement in keeping with the needs of its most critical users. From its development lessons can be learnt on making advanced technology user friendly and responsive.