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The AR-15 is an American assault rifle produced by ArmaLite, and the basis for the AR-15 family of weapons. It is the basis for the M16 and M4 series of service rifles currently in use by the U.S. military, the C7 and C8 series of service rifles currently in use by the Canadian military, and for many semi-automatic rifles currently manufactured by several companies.


The AR-15 is a derivative of the original AR-10; it came about due to the fact that the U.S. Army was forced to revisit the idea of a more lightweight rifle that fired an intermediate cartridge.

The AR-15 was designed around this idea in 1957[2], being an AR-10 that was scaled down to take .223 Remington cartridges. The U.S. Air Force and the U.S. Army adopted AR-15 variants (as the M16), and modified the .223 Remington cartridge slightly (by switching the powder to one that would produce a higher velocity), this cartridge becoming the 5.56x45mm NATO.

The design of the AR-15 was eventually sold to Colt, who produced their own modified models and were adopted by the United States military.

The AR-15 and its variants have seen military service in the Vietnam War, the War in Iraq, and the War in Afghanistan. AR-15 variants are widely used by law enforcement in the United States, replacing the 9mm SMGs that preceded them due to their superior terminal ballistics while still maintaining a similar compact size. AR-15 variants are also common in civilian markets across the world, usually in semi-automatic. These semi-automatic variants would be, by definition, no longer assault rifles, however when they were first released to the American public in 1959, at least on the earliest models, they were capable of fully automatic fire. These original fully automatic AR-15s are not common, and surely extremely expensive compared to a semi-automatic.

Design details

The AR-15 is a gas-operated assault rifle using the direct impingement recoil system, where gases work directly on the bolt to cycle it. The bolt rotates under recoil pressure to unlock it, allowing a cycling of the mechanism to eject the spent casing and load a live round into the chamber.

Later civilian model AR-15s are not assault rifles, but typically classified as sporting rifles due to the lack of automatic fire, a fact that remains true for the vast majority of its civilian derivatives.


The ArmaLite AR-15 fires .223 Remington cartridge, with most examples also being capable for the slightly increased powder loads present in 5.56mm NATO cartridges.

Military Variants

U.S. Military Variants
Canadian Military Variants


External Links