The AR15, or Armalite model 15, was designed by Eugene Stoner and his team of engineers in the 1960’s.  It was designed for the US military’s trials for a new battle rifle.  At the time the US military was using the M-14.

While working for Armalite, a division of the Fairchild Aircraft & Engine Corporation, Eugene Stoner developed a new rifle that utilized a more non traditional material makeup.  He used aluminum alloys and plastics to develop the lighter 5.56 mm version of the AR-10.

Eugene Stoner designed the AR15 around the .222 Remington cartridge, but at the request of the Army, Stoner re-chambered it in the .223 Remington that propelled a 55-grain bullet at roughly 3000 ft per second.

After lengthy evaluation and revisions, the AR15 rifle was only adopted by the U.S. Air Force for use by its base security personnel. For a variety of political reasons, the Army did not select the rifle. However, as America became involved in the Vietnam War, Secretary of Defense James McNamara cut through the Army Ordnance Department’s red tape and selected the AR15 for issuance to troops. The Army gave it the military designation of "M16".

In the Vietnam War, the rifle initially earned a reputation as being prone to jamming and stoppages. This was, in hindsight, due to three primary factors: 1) insufficient training of the troops on weapons maintenance, 2) poor-to-non-existent distribution of cleaning kits to those same troops in the field, and 3) improperly formulated .223 Remington ammunition which caused heavy fouling, a primary cause of stoppages. Eventually, the situation was recognized and remedied as troops were properly trained to keep their weapons clean and well-lubricated, issued proper cleaning kits, and issued .223 Remington ammunition that was properly formulated to burn cleanly.

Today, the AR15 rifle has become really one the most highly engineered and refined battle rifles of modern armies. It has since earned a reputation for reliability and accuracy, and has been in service in all branches of U.S. Armed Forces now for nearly 30 years. In the process, it has been upgraded from the “M-4” to the "M16", to the "M16-A1", all the way through the latest "M16-A4". The U.S. Marine Corps and the U.S. Military Special Operations Command also currently issue to its troops, the M4 rifle. For these Special Forces, the M-4 has also been in certain instances reconfigured to fire "full auto", as opposed to "tri-burst".

The current generation of military M16’s and civilian AR15 models differ from the originals in many ways, reflecting the improvements and refinements of the rifle over the last 30 years. 

What’s in a Name? The name, "AR15", in general is used by the shooting public in reference to all current rifles, regardless of the manufacturer made to look, function, and swap-parts with the AR15. Non-military contract AR15’s are also commonly referred to as "clones". The actual and original "AR15", manufactured by ArmaLite has been discontinued for political reasons. Each manufacturer of AR15-patterned rifles now has its own moniker for the rifle these days; like Colt’s "Match Target", Bushmaster’s "XM15E2", and DPMS’s "Panther".