AR-15 style rifle
An AR-15 style rifle is a lightweight semi-automatic rifle based on the ArmaLite AR-15 design, which is itself a scaled-down derivative of Eugene Stoner's AR-10 design. ArmaLite sold the patent and trademarks to Colt's Manufacturing Company in 1959. After Colt's patents expired in 1977, Colt retained the trademark and is the exclusive owner of the "AR-15" designation.
The Public Safety and Recreational Firearms Use Protection Act restricted the Colt AR-15 and some derivatives from 1994 to 2004, although it did not affect rifles with fewer features.After the term modern sporting rifles was coined in 2009 by the US National Shooting Sports Foundation, a firearms industry trade association, it was quickly adopted by the trade association and some manufacturers.
An expanded marketplace emerged with many manufacturers producing their own version of the AR-15 design for commercial sale.
In the 2010s, AR-15 style rifles became one of the "most beloved and most vilified rifles" in the United States, according to The New York Times. The rifle has been promoted as "America's rifle" by the National Rifle Association. Its steadily increasing popularity is in part due to "the amount of attention through politics and media that is devoted to banning or restricting AR pattern rifles", and additionally because of the large number of styles and variants being produced by many different manufacturers. The rifles are controversial in part due to their use in mass shootings.