Editing Automatic rifle (section)

===M16 rifle===
{{main|M16 rifle}}

The first confrontations between the AK-47 and the M14 ([[assault rifle]] vs [[battle rifle]]) came in the early part of the [[Vietnam War]]. Battlefield reports indicated that the M14 was uncontrollable in automatic mode and that soldiers could not carry enough ammo to maintain fire superiority over the AK-47.<ref>Lee Emerson [http://www.imageseek.com/m1a/M14_RHAD_Online_Edition_061010.pdf M14 Rifle History and Development] {{Webarchive|url=https://web.archive.org/web/20171215062553/http://www.imageseek.com/m1a/M14_RHAD_Online_Edition_061010.pdf |date=2017-12-15 }}. October 10, 2006</ref> A replacement was needed: A medium between the traditional preference for high-powered rifles such as the M14, and the lightweight firepower of the M2 Carbine.

[[File:AR-10 in the National Firearms Museum.jpg|thumb|AR-10 rifle]]
[[File:ArmaLite AR-15 SPAR 3240 DEC. 17. 2004.png|thumb|ArmaLite [[AR-15 style rifle|AR-15]]]]
[[File:M16A1 brimob.jpg|thumb|American 5.56×45mm [[M16A1]]]]

As a result, the Army was forced to reconsider a 1957 request by General Willard G. Wyman, commander of the U.S. Continental Army Command (CONARC) to develop a .223 caliber (5.56&nbsp;mm) select-fire rifle weighing 6&nbsp;lbs (2.7&nbsp;kg) when loaded with a 20-round magazine.<ref name="ReferenceA"/> The 5.56mm round had to penetrate a standard U.S. [[helmet]] at 500 yards (460 meters) and retain a velocity in excess of the speed of sound while matching or exceeding the wounding ability of the .30 Carbine cartridge.<ref>Hutton, Robert (ed.), ''The .223'', Guns & Ammo Annual Edition, 1971.</ref>

This request ultimately resulted in the development of a scaled-down version of the [[ArmaLite AR-10]], called [[ArmaLite AR-15]] rifle.<ref>{{cite book|last=Ezell |first=Edward Clinton |title=Small Arms of the World|year=1983|publisher=Stackpole Books|location=New York |isbn=978-0-88029-601-4|pages=46–47}}</ref><ref name="nodakspud.com">Peter G. Kokalis [http://www.nodakspud.com/RetroAR15.pdf Retro AR-15] {{Webarchive|url=https://web.archive.org/web/20221215125009/http://www.nodakspud.com/RetroAR15.pdf |date=2022-12-15 }}. nodakspud.com</ref><ref name="m-14parts.com">Danford Allan Kern [http://www.m-14parts.com/M14toM16.pdf The influence of organizational culture on the acquisition of the m16 rifle] {{Webarchive|url=https://web.archive.org/web/20131105215841/http://www.m-14parts.com/M14toM16.pdf |date=2013-11-05 }}. m-14parts.com. A thesis presented to the Faculty of the US Army Command and General Staff College in partial fulfillment of the requirements for the degree MASTER OF MILITARY ART AND SCIENCE, Military History. Fort Leavenworth, Kansas 2006</ref> However, despite overwhelming evidence that the AR-15 could bring more firepower to bear than the M14, the Army opposed the adoption of the new rifle.<ref name="m-14parts.com"/> In January 1963, Secretary of Defense Robert McNamara concluded that the AR-15 was the superior weapon system and ordered a halt to M14 production.<ref name="m-14parts.com"/> At the time, the AR-15 was the only rifle available that could fulfill the requirement of a universal infantry weapon for issue to all services. After modifications (Most notably: the charging handle was re-located from under the carrying handle like AR-10 to the rear of the receiver),<ref name="nodakspud.com"/> the new redesigned rifle was subsequently adopted as the [[M16 rifle|M16]].<ref name="m-14parts.com"/><ref name="autogenerated5">[http://apps.dtic.mil/dtic/tr/fulltext/u2/a953110.pdf Report of the M16 rifle review panel] {{Webarchive|url=https://web.archive.org/web/20150924123134/http://www.dtic.mil/dtic/tr/fulltext/u2/a953110.pdf |date=2015-09-24 }}. Department of the Army. dtic.mil. 1 June 1968</ref>

The M16 entered U.S. service in the mid-1960s and was much lighter than the M14 it replaced, allowing soldiers to carry more ammunition.<ref name="autogenerated5"/> Despite its early failures, the M16 proved to be a revolutionary design and stands as the longest continuously serving rifle in American military history.<ref name="smallarmsreview.com">{{cite journal|url=http://www.smallarmsreview.com/display.article.cfm?idarticles=2434 |journal=Small Arms Review |volume=5|issue=7 |title=M14 vs. M16 in Vietnam |first=Robert |last=Bruce|date=April 2002}}</ref><ref>{{Citation | newspaper = GX. The Guard Experience | title = The Pride of the Guard | first = Major Darrin | last = Haas | volume = 10 | issue = 3 | year = 2013 | page = 67 }}.</ref> It is a benchmark against which other assault rifles are judged,<ref name="m-14parts.com"/> and used by 15 NATO countries, and more
than 80 countries worldwide<ref name=colt_customers>[http://www.colt.com/mil/customers.asp Customers / Weapon users]. Colt Weapon Systems. {{webarchive |url=https://web.archive.org/web/20110902033712/http://www.colt.com/mil/customers.asp |date=2 September 2011 }}</ref>