Things you should must know about AR15

"AR-15" redirects here. For the select-fire rifle of a similar name, see ArmaLite AR-15. For other uses, see AR-15 (disambiguation). Colt AR-15 AR-15 Sporter SP1 Carbine.JPG A carbine variant of the Colt AR-15 Type Semi-automatic rifle Place of origin United States Service history In service 1963–present Production history Designer Eugene Stoner, Jim Sullivan, Bob Fremont Manufacturer Colt Variants see List of Colt AR-15 variants Specifications Barrel length 20 inches (510 mm) (standard) 16 inches (410 mm) (carbine) 24 inches (610 mm) (target) Cartridge .223 Remington 5.56×45mm NATO Action Direct impingement Effective firing range ~550 metres (600 yd) Feed system Issued with 5-, 10-, 20- & 30-round STANAG magazines Sights Fixed adjustable front and rear iron sights Detachable carrying handle with adjustable rear iron sight assembly Picatinny rails, which allows the use of various scopes and sighting devices The Colt AR-15 is a lightweight, 5.56×45mm, magazine-fed, gas-operated semi-automatic rifle. It was designed to be manufactured with the extensive use of aluminum alloys and synthetic materials. It is a semi-automatic version of the United States military M16 rifle. Colt's Manufacturing Company currently uses the AR-15 trademark for its line of semi-automatic AR-15 rifles that are marketed to civilian and law-enforcement customers.