Editing M2 Browning (section)

==Variants and derivatives==

===Manufacturers===
Licensed historic production:<ref>accessed 3 September 2023, https://www.hitechcreations.com/wiki/index.php/M2_Browning_machine_gun</ref><ref>accessed 3 September 2023, Royal Canadian Mounted Police (RCMP), Canadian Firearms Program, Firearms Reference Table (FRT)</ref>

* [[Aircraft Armaments Incorporated]] (AAI)
* [[Australian Defence Industries]]
* Canadian Arsenals Limited (CAL)
* [[Colt's Manufacturing Company|Colt's Patent Fire Arms Company]]
* Buffalo Arms Company
* three divisions of [[General Motors]]: [[AC Spark Plug|AC Sparkplug]]; [[Frigidaire]]; and Brown-Lipe-Chapin<ref>Accessed 3 September 2023, https://usautoindustryworldwartwo.com/General%20Motors/onemillionbrownings.htm</ref>
* [[High Standard Manufacturing Company]]
* Kelsey Hayes Wheel Company
* [[Saco-Lowell Shops]]
* [[Savage Arms|Savage Arms Corporation]]
* [[Springfield Armory]] (US arsenal), and
* [[Sumitomo Heavy Industries]]
* Wayne Pump Company
Current production (2023):{{Citation needed|date=June 2024}}
* [[Canik Arms]]<ref>{{cite web | url=https://www.canikarms.com/en/products_detail/canik-m2-qcb | title=Canik Arms }}</ref>
* FN Herstal (Fabrique Nationale)
* General Dynamics
* [[U.S. Ordnance|US Ordnance]]
* Ohio Ordnance Works Inc, and
* Manroy Engineering (UK)

===Variants===
{{Multiple image
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| image1            = Cal50 Browning 2REI 2.jpg
| caption1          = An M2HB in the [[2nd Foreign Infantry Regiment|French Foreign Legion's 2nd Infantry Regiment]] during an exercise
| image2            = Operação Ágata 11 (27209909483).jpg
| caption2          = [[Jungle warfare|Jungle Infantry]] soldier of the [[Brazilian Army]] manning an M2HB in the [[Amazon rainforest]]
}}

The basic M2 was deployed in U.S. service in a number of subvariants, all with separate complete designations as per the US Army system. The basic designation as mentioned in the introduction is Browning Machine Gun, Cal. .50, M2, with others as described below.

The development of the [[M1921 Browning machine gun|M1921]] water-cooled machine gun which led to the M2, meant that the initial M2s were, in fact, water-cooled. These weapons were designated Browning Machine Gun, Cal. .50, M2, Water-Cooled, Flexible. There was no fixed water-cooled version.

Improved air-cooled heavy barrel versions came in three subtypes. The basic infantry model, Browning Machine Gun, Cal. .50, M2, HB, Flexible, a fixed developed for use on the [[M6 Heavy Tank]] designated Browning Machine Gun, Cal. .50, M2, HB, Fixed, and a "turret type" whereby "Flexible" M2s were modified slightly for use in tank turrets. The subvariant designation Browning Machine Gun, Cal. .50, M2, HB, TT was only used for manufacturing, supply, and administration identification and separation from flexible M2s.

A number of additional subvariants were developed after the end of World War II. The M2 Heavy Barrel, M48 Turret Type was developed for the commander's cupola on the [[M48 Patton]] tank. The cupola mount on the M48A2 and M48A3 was thoroughly disliked by most tankers, as it proved unreliable in service.<ref>{{cite book |last=Zumbro |first=Ralph |date=1986 |title=Tank Sergeant |publisher=Presidio Press |page=92 |isbn=978-0-89141-265-6}}</ref>{{Secondary source needed|date=March 2022}} An externally mounted M2 was later adopted for the commander's position on the [[M1 Abrams]] tanks. Three subvariants were also developed for use by the [[U.S. Navy]] on a variety of ships and watercraft including the soft mount and fixed type versions. The fixed types fire from a [[solenoid]] trigger and come in left- or right-hand feed variants for use on the Mk 56 Mod 0 dual mount and other mounts.

Huaqing Machinery has made a clone of the M2HB known as the CS/LM6, which was released publicly in 2010 at foreign weapons expo conventions.<ref name="LM6">{{cite web |url=http://www.qbq.com.cn/a/bencandy.php?fid=73&aid=1632&page=3 |title=第四届中国（北京）国际警用装备及反恐技术装备展览会新品呈献 - 本刊专递 - QBQ-轻兵器 |trans-title=New products presented at the 4th China (Beijing) International Police Equipment and Anti-terrorism Technology and Equipment Exhibition - Special Issue - QBQ - Light Weapon |language=zh |website=QBQ.com.cn |access-date=2018-08-29 |archive-url=https://web.archive.org/web/20180829105924/http://www.qbq.com.cn/a/bencandy.php?fid=73&aid=1632&page=3 |archive-date=2018-08-29 |url-status=dead}}</ref> It was made with a picatinny rail on the receiver in order to have quick installation of various optics.<ref name="LM6"/> The original M2HB tripod and parts can be used on the CS/LM6.<ref>{{cite web |url=http://www.zgjunshi.com/Article/Class38/Class88/Class121/200803/20080301200344.html |title=中国版M2HB：CS/LM6 0.50英寸重机枪 |trans-title=Chinese version of M2HB: CS/LM6 0.50 inch heavy machine gun |language=zh |website=Zgjunshi.com |access-date=2018-08-29 |archive-url=https://web.archive.org/web/20170621073633/http://zgjunshi.com/Article/Class38/Class88/Class121/200803/20080301200344.html |archive-date=2017-06-21 |url-status=live}}</ref>

===M2A1===
[[File:PEO M2E2-QCB HMG.jpg|thumb|M2E2 modification with quick-change barrel (QCB)]]

When the M2 was first being designed, John Browning faced two design challenges. With the machine tools available at that time, the dimensions that established the location of the bolt face and the depth of the chamber could not be held tightly enough to control the fit of the cartridge in the chamber. The round can be too tight in the chamber and the gun would not fire, or be too loose in the chamber, resulting in a stoppage or ruptured cartridge. The other dimension that could not be held closely enough was when the firing pin would fall. The solution to these problems was adjustable timing and headspace ("Timing" is the adjustment of the gun so that firing takes place when the recoiling parts are in the correct position for firing; "headspace" is the distance between the face of the bolt and the base of the cartridge case, fully seated in the chamber); the operator had to screw the barrel into the barrel extension, moving the barrel toward the bolt face to reach the proper headspace with simple gauges to allow the operator to adjust to the proper dimensions. By the late 20th century, the M2 was the only adjustable headspace weapon in the U.S. inventory. With rising reports of injuries from improperly headspaced weapons, the U.S. military held a competition for a quick change barrel conversion kit with fixed timing and headspace in 1997. Three companies offered kits and [[Saco Defense]] won the competition. However, funding was lost before the design could be fully evaluated and the program ended. In 2007, the military found money to start a new competition. Saco Defense had since been acquired by [[General Dynamics]], which won the competition.<ref>{{cite journal |url=http://sadefensejournal.com/wp/?p=428 |title=New .50 Cal Machine Guns, No Tanks |first=George |last=Kontis |date=19 August 2011 |journal=Small Arms Defense Journal |volume=1 |number=4 |url-status=dead |archive-url=https://web.archive.org/web/20131014190604/http://sadefensejournal.com/wp/?p=428 |archive-date=2013-10-14}}</ref>

[[File:RSOV at National War College April 19, 2001.JPEG|thumb|U.S. Army [[Ranger Special Operations Vehicle]] armed with RAMO M2HB-QCB machine gun]]
On 15 October 2010, the ''M2A1'' heavy machine gun was type classified by the U.S. Army. Formerly known as the M2E2, the M2A1 incorporates improvements to the design including a quick change barrel (QCB) with a removable carrying handle, a new slotted flash suppressor that reduces muzzle flash by 95 percent, fixed headspace and timing, a modified bolt, and a manual trigger block safety. When a standard M2 had a barrel change, the headspace and timing had to be manually set. Improper adjustment could damage the weapon and cause serious injury to the user. Fixed headspace and timing reduces risk, and the carrying handle allows the barrel to be switched in seconds.<ref>{{cite web |url=http://peosoldier.armylive.dodlive.mil/2011/01/03/M2a1/ |title=Ma Deuce version M2A1 - Proven Performer gets an Upgrade |first=D. |last=Dawson |date=3 January 2011 |website=PEOSoldier.mil |url-status=dead |archive-url=https://web.archive.org/web/20130219061002/http://peosoldier.armylive.dodlive.mil/2011/01/03/M2a1/ |archive-date=2013-02-19}}</ref><ref>{{cite web |url=http://www.defenseindustrydaily.com/ma-deuce-still-going-strong-03539/ |title=Ma Deuce Still Going Strong |date=1 November 2012 |website=Defense Industry Daily |url-status=dead |archive-url=https://web.archive.org/web/20130127084019/http://www.defenseindustrydaily.com/ma-deuce-still-going-strong-03539/ |archive-date=2013-01-27}}</ref> In June 2011, the Army began conversion of M2HB machine guns to M2A1s.<ref>{{cite web |url=http://www.thefirearmblog.com/blog/2011/08/06/army-to-convert-browning-M2-to-M2a1/ |title=Army to convert Browning M2 to M2A1 |date=6 August 2011 |website=The Firearm Blog |url-status=dead |archive-url=https://web.archive.org/web/20121114054200/http://www.thefirearmblog.com/blog/2011/08/06/army-to-convert-browning-M2-to-M2a1/ |archive-date=2012-11-14}}</ref> The M2A1 was named one of the greatest Army inventions of 2011.<ref>{{cite web |url=http://www.thefirearmblog.com/blog/2012/09/21/M2a1-among-greatest-army-inventions-of-2011/ |title=M2A1 Among Greatest Army Inventions of 2011 |date=21 September 2012 |website=The Firearm Blog |url-status=dead |archive-url=https://web.archive.org/web/20121127194519/http://www.thefirearmblog.com/blog/2012/09/21/M2a1-among-greatest-army-inventions-of-2011/ |archive-date=2012-11-27}}</ref> As of 30 November 2012, 8,300 built or converted M2A1s had been fielded by the U.S. Army; the program will upgrade the Army's entire M2 inventory of more than 54,000 guns.<ref>{{cite web |url=http://www.army.mil/article/92130/ |title=M2A1 Machine Gun Features Greater Safety, Heightened Lethality |first=Kevin |last=Doell |date=30 November 2012 |website=Army.mil |url-status=live |archive-url=https://web.archive.org/web/20131015043857/http://www.army.mil/article/92130/ |archive-date=2013-10-15}}</ref> The [[U.S. Marine Corps]] plans to upgrade all of their ground-mounted M2s to M2A1 standard from 2016 to 2018.<ref>{{cite news |url=http://www.marinecorpstimes.com/story/military/tech/2015/09/17/marines-unveil-plan-modernize-their-small-arms-arsenal/72006282/ |title=Marines unveil plan to modernize their small arms arsenal |first= James K. |last=Sanborn |date=17 September 2015 |newspaper=Marine Corps Times |url-status=live |archive-url=https://web.archive.org/web/20160105102710/http://www.marinecorpstimes.com/story/military/tech/2015/09/17/marines-unveil-plan-modernize-their-small-arms-arsenal/72006282/ |archive-date=2016-01-05}}</ref> The first phase of conversions was completed in March 2017, with 3,600 M2A1s planned to be fielded by the Marines in total.<ref>{{cite news |url=https://www.marinecorpstimes.com/articles/improved-50-caliber-machine-gun-hits-fleet |title=Improved .50-caliber machine gun hits fleet |first=Todd |last=South |date=27 April 2017 |newspaper=Marine Corps Times |url-status=live |archive-url=https://web.archive.org/web/20170428002038/https://www.marinecorpstimes.com/articles/improved-50-caliber-machine-gun-hits-fleet |archive-date=2017-04-28}}</ref> The [[Israel Defense Forces]] adopted the M2-HQCB (the commercial version of the M2A1) in 2012 as a replacement to the M2HB.<ref>{{cite web |url=http://www.idf.il/1133-14686-he/Dover.aspx |title=הכירו את כלי הנשק החדשים של זרוע היבשה |trans-title=Familiarize yourself with the new weapons of the land arm |date=2012 |website=[[Israel Defense Forces]] |language=he |url-status=dead |archive-url=https://web.archive.org/web/20160911000141/http://www.idf.il/1133-14686-he/Dover.aspx |archive-date=11 September 2016}}</ref>

=== 13,2 mm FN Browning ===
One derivative of the M2 Browning is the [[Mitrailleuse d´Avion Browning - F.N. Calibre 13,2 mm]], more commonly known as the FN Browning M.1939. The FN Browning M.1939 was a heavily modified M2 Browning for aircraft use designed by [[FN Herstal]] for export. Their aim was to make a light, reliable heavy machine gun with the same damage output as a 20&nbsp;mm autocannon. To achieve this, they raised the firing rate to 1080 rpm and gave it a more powerful cartridge in the form of the [[13.2×99mm Hotchkiss]].<ref>{{Cite book |title=La mitrailleuse Browning FN booklet}}</ref> This cartridge was a popular Eurasian analog of [[.50 BMG]] developed independently in 1920s with a 13.2&nbsp;mm bullet (.52 in) and more propellant. A new projectile was designed for this gun. It was of a high explosive type and was designed to take down a small aircraft with a single hit. Tests showed that it was very effective against both cloth and aluminum skinned aircraft.<ref>{{Cite book |title=La mitrailleuse Browning FN, kapitel XII. Les munitions F.N. calibre 13,2 mm}}</ref>

Due to the aforementioned improvements, the gun received interest from numerous nations when it entered the export market in 1939. Due to the start of World War 2 and the invasion of [[Belgium]] it was exported to only [[Romania]] and [[Sweden]].<ref name=":0" /> Sweden was able to buy the majority of the weapons along with the blueprints to produce the weapon on their own without paying for a license. In Sweden, the weapon received the designation Automatkanon m/39, short Akan m/39, meaning Autocannon m/39 and was later produced by [[Ericsson]] as the Akan m/39A. Sweden also gave the blueprints to [[Finland]] so they could produce the weapon. Since Finland was already producing 12.7&nbsp;mm ammunition, the Finnish variant was rechambered to 12.7&nbsp;mm (.50 BMG). The Finnish variant was designated VKT 12,70 LKk/42 and was produced by Finland.