M16 (rifle)

M16 is the U.S. Military designation for a family of rifles derived from the Armalite AR-15. It is an assault rifle which fires NATO standard 5.56 mm ammunition. It has been the primary infantry rifle of the United States military since 1967, is in use by 15 NATO countries, and has been the most produced firearm in its caliber.

Future replacement?

Overview

In the 1980s, many soldiers who had been equipped with M16A1s were given a M249 (in addition to the M60s it replaced). In the 1990s, the adoption of the M4 Carbine meant many more M16A2s would be replaced by it. The Air Force currently plans to replace all its M16s with M4s according to a 2004 presentation. The M16A2 still remains the main US service rifle in the Army, though in the 2000s the Marine Corps moved to M16A4 rifles. Also the M16 never entirely replaced the M14 in all roles, which continues to be used in a number of niche applications throughout the Armed Forces.

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The M16 family itself would have potentially been replaced at various points, and its longevity is in part due to a series of delays and failures in projects to replace it. It was going to be replaced by the winner of the Advanced Combat Rifle program, but none scored high enough to be worth the cost of changing over. It was also potentially going to be replaced by the SABR, from the OICW project. The rifle originally planned by the OICW project was put on hold around the turn of century, in favor of simpler new 5.56 mm rifle project, that offered less far-reaching improvements. The XM8 rifle which resulted, was also potentially going to replace the M16 family. However, this too ran into problems around 2004-5 and was put on hold in favor of a competition. The new competition itself was put on hold in 2005 to take into account input from other services.

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History

Throughout the 1970s the Army experimented with various materials to replace the brass casings. Brass has a number of features that make it almost ideal for a cartridge, including low-friction against steel which made it easier to extract, and its ability to carry away a considerable amount of heat from the weapon and thereby keep it cooler. However brass is also heavy and expensive, replacing it would lower both the cost and weight of the ammunition.

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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 one reason or another. 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.

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Later in the 1980s the Advanced Combat Rifle program was run to find a replacement for the M16. The Army was pressing for a 100% increase in the ability for infantry to hit their targets, in the same way that SALVO had aimed to increase effectiveness by 100% through increased rate of fire.

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Colt entered a modified M16A2 known as the Colt ACR, which used duplex rounds, used a system that lowered recoil by 40% to allow better repeating shots, and added a 3.5x scope. This weapon, designated M16A2E2, also featured a "guide" of sorts as part of a special handguard developed by the US Army Human Engineering Laboratory (HEL) designed to assist in snap-shooting, and a carbine style stock very similar to the recent stock developed by the Naval Surface Warfare Center, Crane Division.

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The Steyr ACR used new flechette ammunition that was nominally called 5.56 mm, with a very high 4750 ft/s (1450 m/s) muzzle velocity. Other variants experimented with caseless ammunition technologies as well.

Related Topics:
Steyr ACR - Caseless ammunition

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Although they all offered some improvement, none came close to the benchmark set for the testing.

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More recently the Army has started the XM8 system project for a radically improved weapon. However, the program has been shelved in favor of an open competition for what is now known as OICW Increment 1. (Increment 2 is the stand-alone airbursting grenade launcher known as the XM25, and Increment 3 will be the XM29, a weapon which combines the earlier two increments.)

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