The AR-15 is a lightweight, magazine-fed, air-cooled, autoloading centerfire rifle designed by Eugene Stoner of the Armalite corporation who developed it as a smaller version of the AR-10. Armalite sold its rights to the AR-10 and AR-15 to Colt in 1959 after which the AR-15 was adopted by the United States military under the designation M16. Colt retained the name AR-15 for its semi-automatic civilian/law enforcement model. Today the AR-15 and its variations are manufactured by a plethora of companies and have captured the affection of sport shooters and police forces around the world.

Some notable and revolutionary features of the AR-15:

• An aircraft grade aluminum receiver
• Modular design allows many configurations, as well as rapid swapping of parts for field repairs
• Small caliber
• Synthetic Stock and Grips
• Carry handle
• bayonet lug located under the front sight
• front and rear sights are adjustable for windage

In the United States, variants with certain features were prohibited for new sales to civilians during the period 1994-2004.

The Colt AR15 SP1 has been designed to look and feel like the M16A1 battle rifle. The M16A1 battle rifle is select-fire, meaning that it can switch between semi-automatic and fully-automatic fire modes at the discretion of the user, while the Colt AR15 SP1 can only be fired in semi-automatic mode (one shot per pull of the trigger.)

Technical data

• Caliber: .223 Rem/5.56x45 mm NATO
• Length: 39 in
• Mass: 3.4 kg (7.5 lb)
• Barrel: 20 in
• Rifling: 1:12
• Magazine capacity: 20, 30; 100 (see below)

Standard issue magazines are 20 or 30 round double stack magazines; a 100 round Beta C-MAG twin drum magazine also exists.

See also

• M4 Carbine
• M16

External links

• Modern Firearms article
• ar15.com
• Armalite
• Bushmaster
• Colt
• Olympic Arms