Editing Colt AR-15 (section)

==AR-15 style rifle==
{{main|AR-15 style rifle}}
After Colt's patents expired in 1977,<ref>{{cite book|last=Zimba|first=Jeff|title=The Evolution of the Black Rifle: 20 Years of Upgrades, Options, and Accessories|url=https://books.google.com/books?id=bCFjCgAAQBAJ&pg=PT10|year=2014|publisher=Prepper Press|isbn=978-0-692-31726-6|page=10}}</ref> other manufacturers began to copy the design of the Colt AR-15. The term "AR-15" is a Colt registered trademark which it uses only to refer to its line of semi-automatic rifles. Other manufacturers marketed generic AR-15s under other designations, frequently referred to as AR-15s, as are some rifles and carbines not based on the AR-15 design.<ref>{{Cite news|url=https://www.newyorker.com/culture/culture-desk/the-year-in-nine-objects|title=The Year in Nine Objects|last=Walker|first=Rob|author-link=Rob Walker (journalist)|date=2016-12-30|magazine=[[The New Yorker]]|access-date=2017-11-06|issn=0028-792X|archiveurl=https://web.archive.org/web/20230406100351/https://www.newyorker.com/culture/culture-desk/the-year-in-nine-objects|archive-date=April 6, 2023}}</ref>

AR-15 style rifles are available in a wide range of configurations and [[Caliber|calibers]] from a large number of manufacturers. These configurations range from standard full-size rifles with 20-inch barrels, to short carbine-length models with 16-inch barrels, adjustable length stocks and optical sights, to long range target models with 24-inch barrels, bipods and high-powered scopes. These rifles may also have [[Gas-operated reloading#Short-stroke fixed|short-stroke gas piston system]], forgoing the direct gas system standard in AR-15 rifles. These calibers include 5.56×45mm NATO, [[5.7×28mm]], [[6.8mm Remington SPC]], [[.300 Blackout]], [[9×19mm Parabellum]] and [[.458 SOCOM]] to name a few.<ref>U.S. Military Small Arms Ammunition Failures and Solutions, GK Roberts, NDIA Dallas, TX, May 21, 2008 {{cite web |url=http://www.dtic.mil/ndia/2008Intl/Roberts.pdf |title=Archived copy |access-date=2011-02-04 |url-status=dead |archive-url=https://web.archive.org/web/20110628234759/http://www.dtic.mil/ndia/2008Intl/Roberts.pdf |archive-date=June 28, 2011 |df=mdy-all }}</ref><ref>[http://archives.gunsandammo.com/content/evolution-ar Evolution of an AR | Gear | Guns & Ammo] {{webarchive |url=https://web.archive.org/web/20110915075030/http://archives.gunsandammo.com/content/evolution-ar |date=September 15, 2011 }}. Archives.gunsandammo.com (August 29, 2011). Retrieved on 2011-09-27.</ref>