M61 Vulcan: Difference between revisions

{{shortShort description|20 mm gatling Gatling-type rotary cannon}}

|used_by= United States, some [[NATO]] members, [[South Korea]], [[Saudi Arabia]], and others

|weight= {{ubli|M61A1: {{cvt|248|lb|kg}}<br />|M61A2: {{cvt|202|lb|kg}} (light barrel), {{cvt|228|lb|kg}} (heavy barrel) }}

|range=About {{cvt|20009842|ft|m|sigfig=1}}

The '''M61 Vulcan''' is a [[Hydraulic machinery|hydraulically]], electrically, or [[pneumatics|pneumatically]] driven, six-[[Gun barrel|barrel]], air-cooled, electrically fired [[Gatling gun|Gatling-style]] [[rotary cannon]] which fires [[20 mm caliber|{{cvt|20 x 102|mm|in|3}}]] rounds at an extremely high rate (typically 6,000 rounds per minute). The M61 and its derivatives have been the principal cannon armament of [[United States Armed Forces|United States military]] [[fixed-wing aircraft]] for over sixty years.<ref name ="fas_m61"/>

The M61 was originally produced by [[General Electric]]. After several mergers and acquisitions, it is currently produced by [[General Dynamics]] {{asof|2000|lc=y}}.<ref name="fas_m61" />

At the end of [[World War II]], the [[United States Army Air Forces]] began to consider new directions for future [[military aircraft]] guns. The higher speeds of [[jet engine|jet-powered]] [[fighter aircraft]] meant that achieving an effective number of hits would be extremely difficult without a much higher volume of fire. While captured German designs (principally the [[Mauser MG 213|Mauser MG 213C]]) showed the potential of the single-barrel [[revolver cannon]], the practical rate of fire of such a design was still limited by ammunition feed and barrel wear concerns. The Army wanted something better, combining an extremely high rate of fire with exceptional reliability.<ref name="archive.org">https://archive.org/stream/The_Machine_Gun_V5/The_Machine_Gun_V5_djvu.txt M61 Al, CHAG, and GAU-8/A Machine Guns, History of Vulcan</ref>

In 1947, the [[United States Air Force|Air Force]] became a separate branch of the military. The new Air Force made a request for a new aircraft gun. A lesson of World War II air combat was that German, Italian, and Japanese fighters could attack American aircraft from long range with their cannon main armament. American fighters with [[M2 Browning#AN.2FM2|.50&nbsp;caliber (12.7&nbsp;mm)]] main armament, such as the [[North American P-51 Mustang|P-51]] and [[Republic P-47 Thunderbolt|P-47]], had to be close to enemy aircraft in order to hit and damage them. The [[Hispano-Suiza HS.404|{{cvt|20|mm|in}} Hispano cannon]] carried by the [[Lockheed P-38 Lightning|P-38]] and [[Northrop P-61 Black Widow|P-61]], while formidable against propeller-driven planes, had a relatively low rate of fire in the age of jets, while other cannons were notoriously unreliable.

In 1946, the Army issued General Electric a contract for "Project Vulcan", a six-barrel weapon capable of firing 7,200 rounds per minute (rpm).<ref>{{Cite web |title= The Gatling Gun |access-date=2008-09-28 |url= http://tri.army.mil/lc/cs/csa/aagatlin.htm#M61 |date=5 October 2005 |archive-url= https://web.archive.org/web/20080921095536/http://tri.army.mil/LC/CS/csa/aagatlin.htm |archive-date =2008-09-21 |publisher= Aircraft Armament & Small Arms Product Support Integration Directorate |first1= Paul F |last1= Wahl |first2= Donald R |last2= Toppel |orig-year= Arco Publishing Company, New York, NY, 1965}}</ref> Although European designers were moving towards heavier {{cvt|30|mm|in|3}} weapons for better hitting power, the U.S. initially concentrated on a powerful {{convert |0.60|in|mm|adj= on}} cartridge designed for a pre-war anti-tank rifle, expecting that the cartridge's high [[muzzle velocity]] would be beneficial for improving hit ratios on high-speed targets.<ref name="archive.org"/> The first GE prototypes of the {{convert|0.60|in|mm|adj=on}} caliber T45 were ground-fired in 1949; it achieved 2,500&nbsp;rpm, which was increased to 4,000&nbsp;rpm by 1950. By the early 1950s, the USAF decided that high velocity alone might not be sufficient to ensure target destruction and tested {{cvt|20|and|27|mm|in|sigfig=3}} alternatives based on the {{convert|0.60|in|mm|adj=on}} caliber cartridge. These variants of the T45 were known as the T171 and T150 respectively and were first tested in 1952. Eventually, the standard 20×102&nbsp;mm cartridge was determined to have the desired balance of projectile/explosive mass and muzzle velocity, resulting in an optimum balance of range, accuracy and [[Kinetic energy penetrator|kinetic energy]] on target.<ref>{{Cite web|url=https://www.dau.mil/cop/ammo/DAU%20Sponsored%20Documents/PEO%20Ammo%20Portfolio%20Book%202017.pdf|title=PEO Ammunition Systems|website=dau.mil|archive-url=https://web.archive.org/web/20181106171753/https://www.dau.mil/cop/ammo/DAU%20Sponsored%20Documents/PEO%20Ammo%20Portfolio%20Book%202017.pdf|archive-date=6 November 2018|url-status=live}}</ref>

In 1993, [[General Electric]] sold its aerospace division, including GE Armament Systems along with the design and production tooling for the M61 and GE's other rotary cannon, to [[Martin Marietta]]. After Martin's merger with [[Lockheed Corporation|Lockheed]], the rotary cannon became the responsibility of Lockheed Martin Armament Systems. Lockheed Martin Armament Systems was later acquired by [[General Dynamics]], whowhich currently produceproduces the M61 and its variants {{asof|2000|lc=y}}.<ref name= "fas_m61">{{cite web |url= http://www.fas.org/man/dod-101/sys/ac/equip/m61.htm |title= M61 20mm cannon |access-date= 2009-02-28 |date= 23 April 2000 |publisher= [[Federation of American Scientists]] |archive-url= https://web.archive.org/web/20011214122616/http://www.fas.org/man/dod-101/sys/ac/equip/m61.htm |archive-date= 14 December 2001 |url-status= live }}</ref>

[[File:M-61 Vulcan-28.jpg|thumb|right|An M61 Vulcan and the feed system for an [[McDonnell Douglas F/A-18 Hornet|F/A-18]], on a stand.]]

Each of the cannon's six barrels fires once in turn during each revolution of the barrel cluster. The multiple barrels provide both a very high rate of fire – aroundfire—around 100 rounds per second—and contribute to prolonged weapon life by minimizing barrel erosion and heat generation.<ref>{{Cite book |last=Tucker |first=Spencer C. |url=https://books.google.com/books?id=-oaMBAAAQBAJ&dq=M61+Vulcan++rate+of+fire+%E2%80%93+around+100+rounds+per+second&pg=PA271 |title=Persian Gulf War Encyclopedia: A Political, Social, and Military History: A Political, Social, and Military History |date=2014-08-20 |publisher=ABC-CLIO |isbn=978-1-61069-416-2 |language=en}}</ref> The average time between jams or failures is in excess of 10,000 rounds, making it an extremely reliable weapon.<ref>{{CitationCite neededweb |date=2023-01-31 |title=U.S. SeptemberHypersonic 2014Weapons and Alternatives {{!}} Congressional Budget Office |url=https://www.cbo.gov/publication/58924 |access-date=2023-06-24 |website=www.cbo.gov |language=en}}</ref> The success of the Vulcan Project and its progeny, the very-high-speed Gatling gun, has led to guns of the same configuration being referred to as [[wikt:Vulcan cannon|"Vulcan cannons"]], which can sometimes confuse nomenclature on the subject.{{Citation needed |date = September 2014}}

The self-powered version, the '''GAU-4''' (called '''M130''' in Army service), is [[gas-operated]], tapping gun gas from three of the six barrels to operate the gun gas-driven mechanism. The self-powered Vulcan weighs about {{convert|10|lb|kg|order=flip}} more than its electric counterpart, but requires no external power source to operate, except for an electric inertia starter to initiate gun rotation, allowing the first rounds to be chambered and fired.<ref name="Air Force Manual 11W1-12-4-32"/>

The initial ''M61'' used linked ammunition, but the ejection of spent links created considerable (and ultimately insuperable) problems. The original weapon was soon replaced by the ''M61A1'', with a linkless feed system. Depending on the application, the feed system can be either single-ended (ejecting spent cases and unfired rounds) or double-ended (returning casings back to the magazine). A disadvantage of the M61 is that the bulk of the weapon, its feed system, and ammunition drum make it difficult to fit it into a densely packed airframe.<ref>[https://archive.org/stream/The_Machine_Gun_V5/The_Machine_Gun_V5_djvu.txt Model D Vulcan]</ref>

The feed system must be custom-designed for each application, adding {{cvt|300|to|400|lb|kg|order=flip}} to the complete weapon. Most aircraft installations are double-ended, because the ejection of empty cartridges can cause a foreign-object damage hazard for jet engines and because the retention of spent cases assists in maintaining the center of gravity of the aircraft.<ref>{{Cite web |title=General Dynamics-OTS to supply M61A1 Vulcan 20mm guns for F-16s through FMS |url=https://airrecognition.com/index.php/news/defense-aviation-news/2021/december/7970-general-dynamics-ots-to-supply-m61a1-vulcan-20mm-guns-for-f-16s-through-fms.html |access-date=2023-06-24 |website=airrecognition.com}}</ref> The first aircraft to carry the M61A1 was the C model of the [[F-104 Starfighter|F-104]], starting in 1959.<ref>{{Cite book |last=W.Bowman |first=Bowman, Martin W. |url=httphttps://worldcatbooks.orggoogle.com/oclc/1204135835books?id=OwY0EAAAQBAJ&dq=The+first+aircraft+to+carry+the+M61A1+was+the+C+model+of+the+F-104,&pg=PA152 |title=Lockheed F-104 Starfighter: A History. |date=20192017-11-30 |publisher=Pen &and Sword Books LimitedAviation |isbn=978-1-4738-63286329-63 |oclclanguage=1204135835en}}</ref>{{Page needed|date=July 2022}}

A lighter version of the Vulcan developed for use on the [[F-22 Raptor]], designated M61A2, is mechanically the same as the M61A1, but with thinner barrels to reduce overall weight to {{convert |202|lb|kg|order=flip}}. The rotor and housing have also been modified to remove any piece of metal not absolutely needed for operation and replaces some metal components with lighter-weight materials. The [[F/A-18E/F Super Hornet]] also uses this version.<ref>{{Citation |contribution-url = http://www.airforce-technology.com/projects/fa18/ |title = Projects |contribution = F/A-18E/F Super Hornet Maritime Strike Attack Aircraft |quote = …features...&nbsp;features new lightweight gun system is the General Dynamics M61A2, which has a switchable firing rate of 4,000 or 6,000 rounds per minute and a fully integrated linkless ammunition feed system}}</ref>

File:M61 Vulcan.jpg|An M61 Vulcan at the [[Miramar Airshow]].

Image:AC-130A 20MM Vulcan Cannon Ammo belt.jpg|An M61 ammunition belt.

File:M61A1-Vulcan--Independence-Day-2017-Tel-Nof-IZE-059.jpg|M61 on display.

File:PGU-27-AB-20-102mm-ammunition-m-61-vulcan.jpg|PGU-27 AB training rounds, Brussels 2015.

Practically no powered rotary cannon is supplied with sufficient ammunition for a full minute of firing, due to its weight (at 6,000&nbsp;rpm, the projectiles alone would represent a mass of about {{cvt|600|kg}} for one minute of firing; and by including the brass shell, filling and primer the weight is slightly double that at {{cvt|1225|kg}}). In order to avoid using the 600 to 10001,000 rounds carried by aircraft all at once, a burst controller is generally used to limit the number of rounds fired at each trigger pull. Bursts of from two or three up to 40 or 50 can be selected.<ref>{{Cite web |url=https://www.globalsecurity.org/military/systems/munitions/pgu-28.htm |title=Pgu-27A/B Tp/ Pgu-28A/B Saphei / Pgu-30A/B Tp-T |access-date=23 May 2019 |archive-url=https://web.archive.org/web/20190523213725/https://www.globalsecurity.org/military/systems/munitions/pgu-28.htm |archive-date=23 May 2019 |url-status=live }}</ref> The size of the airframe and available internal space limits the size of the ammunition drum and thus limits the ammunition capacity. When vehicle-mounted, the only limiting factor is the vehicle's safe carry weight, so commensurately larger ammo storage is available.

Until the late 1980s, the M61 primarily used the M50 series of ammunition in various types, typically firing a {{convert|3.5|oz|g|order=flip|adj=on}} projectile at a [[muzzle velocity]] of about {{convert|3380|ft/s|m/s|order=flip}}. A variety of Armorarmor-Piercingpiercing Incendiaryincendiary (API), High Explosivehigh-explosive Incendiaryincendiary (HEI), and training rounds are available.

TheA new PGU-28/B round was developed in the mid-1980s. It is a [[semi-armor-piercing high-explosive incendiary]] (SAPHEI) round, providing improvements in range, accuracy, and power over the preceding M56A3 HEI round.<ref name= GSPGU>{{Cite web |title=PGU-27A/B TP/PGU-28A/B SAPHEI/ GU-30A/B TP-T |url=http://www.globalsecurity.org/military/systems/munitions/pgu-28.htm |publisher=GlobalSecurity.org |access-date=2008-09-28 |archive-url=https://web.archive.org/web/20080916214052/http://www.globalsecurity.org/military/systems/munitions/pgu-28.htm |archive-date=16 September 2008 |url-status=live }}</ref> The PGU-28/B is a "low-drag" round designed to reduce in-flight drag and deceleration, and has a slightly increased muzzle velocity of {{convert |3450|ft/s|m/s|order=flip}}.<ref>{{cite web |title=20MM PGU-28 A/B |url=https://www.gd-ots.com/wp-content/uploads/2017/11/20mm-PGU-28-A-B-F-16.pdf |archive-url=https://web.archive.org/web/20190904002806/https://www.gd-ots.com/wp-content/uploads/2017/11/20mm-PGU-28-A-B-F-16.pdf |archive-date=2019-09-04 |url-status=live |publisher=General Dynamics Ordnance and Tactical Systems}}</ref> However, the PGU-28/B has not been without problems. A 2000 USAF safety report noted 24 premature detonation mishaps (causing serious damage in many cases) in 12 years with the SAPHEI round, compared to only two such mishaps in the entire recorded history of the M56 round. The report estimated that the current PGU-28/B had a potential failure rate 80 times higher than USAF standards permit.<ref>{{Cite report |date=30 November 2001 |title=Ammunition Active |publisher= Airborne Weapons Corrective Action Program |url= https://tercel.mugu.navy.mil/drlog/awcap/volumes/vol8/ammo/v348_prob.pdf |url-status=dead |archive-date=17 October 2004 |archive-url = https://web.archive.org/web/20041017182625/https://tercel.mugu.navy.mil/drlog/awcap/volumes/vol8/ammo/v348_prob.pdf |id=14597 |section= PGU-28/B Premature Detonation in Barrel/Barrel Damage |pages= 1–6}}</ref> Due to safety issues, it was limited to emergency wartime use in 2000.<ref>"''Jane's International Defense Review: IDR'', Volume 36, Issues 1-6"1–6. Jane's Information Group, 2003. "In 2000, the newer-technology PGU-28/B ammunition for the M61 was restricted to emergency wartime use after a series of mishaps."</ref>

The main types of combat rounds and their main characteristics are listed in the table below.:

| 10301,030

| 10301,030

| 10501,050

The Vulcan was first used in aerial combat on 4 April 1965, when four [[North VietnameseVietnam]]ese [[Vietnam People's Air Force MiG-17s]] (VPAF) [[Shenyang JMiG-5|J-517]]s)<ref>Toperczer (MiG-17/MiG-19 Units) p. 65</ref> attacked a force of 10 [[North American F-100 Super Sabre]]s (two of which were assigned weather reconnaissance duties) escorting 48 Vulcan-armed and "bomb-laden" [[Republic F-105 Thunderchief|F-105 Thunderchiefs]], shooting down two of the latter. The MiG Leaderleader and only survivor from the four MiGs, Captain Tran Hanh, reported that U.S. jets had pursued them and that F-105s had shot down three of his aircraft, killing Lieutenantslieutenants Pham Giay, Le Minh Huan, and Tran Nguyen Nam. Capt.Captain Donald Kilgus, piloting an F-100, received an official probable kill with his four [[M39 cannon|M39]] 20&nbsp;mm cannons during the engagement; however no other US pilot reported destroying any MiGs during the battle, leaving open the possibility that at least two of the MiG-17s may have been downed by their own [[anti-aircraft]] fire.<ref>Hobson p. 17</ref><ref>Anderton p. 71</ref><ref>Toperczer (MiG-17/MiG-19 Units) pp. 30, 31, 88</ref>

The first confirmed Vulcan gun kill occurred on 29 June 1966 when [[Major (rank)|Major]] Fred Tracy, flying his F-105 Thunderchief with the 421st TFS, fired 200 rounds of 20&nbsp;mm into a MiG-17 that had just fired a 23&nbsp;mm shell which entered one side of his cockpit and exited the other. When the NVAFVPAF MiG flew in front of him after making hisits pass, Maj. Tracy opened fire on himit.<ref>McCarthy Jr. p. 38, photograph of 23&nbsp;mm cannon exit hole on Maj. Tracy's F-105</ref><ref>Michel III p. 56</ref>

The gun was installed in the Air Force's A-7D version of the [[LTV A-7 Corsair II]] where it replaced the earlier [[United States Navy]] A-7's [[Colt Mk 12 cannon]] and was adopted by the Navy on the A-7C and A-7E.<ref name = Chant1987>{{cite book|first= Christopher |last = Chant |title=A Compendium of Armaments and Military Hardware |url= https://books.google.com/books?id=k9cNAAAAQAAJ&pg=PA115 |year =1987|publisher=Routledge |isbn= 978-0-7102-0720-3 |pages = 65–70, 106, 114–15, 341–43, 363, 389, 404–5}}</ref> It was integrated into the newer [[McDonnell Douglas F-4 Phantom II|F-4E Phantom II]] variants. The F-4 was originally designed without a cannon as it was believed that missiles had made guns obsolete. Combat experience in Vietnam showed that a gun could be more effective than [[guided missiles]] in many combat situations and that an externally carried gun pod was less effective than an internal gun; the first generation of gun pods such as the SUU-16 were not oriented with the sights of the fighter. The improved pods were self-powered and properly synchronized to the sights, while the USAF versions of the F-4 were hastily fitted with internal M61 cannoncannons in a prominent fairing under the nose, well before the war ended (Navy Phantoms never received a cannoncannons, continuing to rely on air-to-air missiles alone). [[Teen Series|The next generation]] of fighters built post-Vietnam incorporated the M61 gun internally.<ref>{{Cite web |url=https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104505/f-16-fighting-falcon/ |title=F-16 Fighting Falcon |access-date=5 December 2018 |archive-url=https://web.archive.org/web/20181213203840/https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104505/f-16-fighting-falcon/ |archive-date=13 December 2018 |url-status=live }}</ref><ref>{{Cite web |url=https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104501/f-15-eagle/ |title=F-15 Eagle |access-date=5 December 2018 |archive-url=https://web.archive.org/web/20181208140916/https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104501/f-15-eagle/ |archive-date=8 December 2018 |url-status=live }}</ref><ref>{{Cite web |url=http://www.navalaviationmuseum.org/attractions/aircraft-exhibits/item/?item=f-14a_tomcat_flightline |title=F-14A Tomcat &#124; National Naval Aviation Museum |access-date=5 December 2018 |archive-url=https://web.archive.org/web/20181205145742/http://www.navalaviationmuseum.org/attractions/aircraft-exhibits/item/?item=f-14a_tomcat_flightline |archive-date=5 December 2018 |url-status=live }}</ref><ref>{{Cite web |url=https://www.boeing.com/history/products/fa-18-hornet.page |title=Boeing: Historical Snapshot: F/A-18 Hornet Fighter |access-date=5 December 2018 |archive-url=https://web.archive.org/web/20181205103355/https://www.boeing.com/history/products/fa-18-hornet.page |archive-date=5 December 2018 |url-status=live }}</ref>

|+ Combat kills using the M61 Vulcan in the Vietnam War 1966–721966–1972<ref>McCarthy Jr. pp. 148–57148–157. Excludes combination air-to-air missile/gun kills.</ref>

|433rd TFS; Pilotpilot, Major B J Bogoslofski, [[Weapon systems officer|WSO]], Captain Richard L Huskey<ref>Davies, Osprey #45, p. 86</ref>

|35th TFS; Thethe F4E was the first Phantom II to enter the war with an internal Vulcan gun.<ref>Michel III pp. 181, 267</ref>

|58th TFS; Firstfirst kill at [[supersonic]] speed ([[mach number|Mach]]&nbsp;1.2); Major Phil Handley/WSO 1LT J. J. Smallwood<ref>Davies, Osprey #55, pp. 37–38</ref>

! colspan="5 bground=black" |

The Vulcan was later fitted into the weapons bay of some [[Convair F-106 Delta Dart]] and [[General Dynamics F-111 Aardvark]] models. It was also adopted as standard in the "teen"-series air superiority fighters,: the [[Grumman F-14 Tomcat]], the [[McDonnell Douglas F-15 Eagle]], [[General Dynamics F-16 Fighting Falcon]], and [[McDonnell Douglas F/A-18 Hornet]]. Other aircraft include the Italian/Brazilian [[AMX International AMX]] (on Italian aircraft only), and the [[F-22 Raptor]]. It was fitted in a side-firing installation on the [[Fairchild AC-119]] and some marks of the [[Lockheed AC-130]] [[gunship]]s, and was used in the tail turrets of both the [[Convair B-58 Hustler]] and [[Boeing B-52 Stratofortress|Boeing B-52H Stratofortress]] bombers.{{efn-lr|The B-52 Vulcans were removed in 1991.}} Japan's [[Mitsubishi F-1]] carried one internally mounted JM61A1 Vulcan with 750 rounds.<ref name=Chant1987 />

The subsequent SUU-23/A uses the ''GAU-4/A'' self-powered Vulcan, with an electric inertia starter to bring it up to speed. Both [[gun pod|pods]] ejected empty cases and unfired rounds rather than retaining them. Both pods contained 1,200 rounds of ammunition, with a loaded weight of {{convert|1615|and|1720|lb|kg|order=flip}} respectively. During service in the [[Vietnam War]], the pods proved to be relatively inaccurate: the pylon mounting was not rigid enough to prevent deflection when firing, and repeated use would misalign the pod on its pylon, making matters worse.{{Citation needed |date = September 2014}}

A variant with much shorter barrels, designated the '''M195''', was also developed for use on the [[U.S. Helicopter Armament Subsystems#AH-1 Cobra|M35 Armament Subsystem]] foras useused on the [[Bell AH-1 Cobra|AH-1G Cobra]] [[helicopter]]. This variant fed from ammunition boxes fitted to the landing skid and was developed to provide the AH-1 helicopter with a longer-range [[suppressive fire]] system before the adoption of the [[US Helicopter Armament Subsystems|M97 Universaluniversal Turretturret]] mounting the [[M197 Gatling gun|M197]] cannon.<ref>{{Cite web |url=https://centaursinvietnam.org/History/ihistoryEqOrd20mm.html |title=20mm Cannon |access-date=23 May 2019 |archive-url=https://web.archive.org/web/20190326104705/http://centaursinvietnam.org/History/ihistoryEqOrd20mm.html |archive-date=26 March 2019 |url-status=live }}</ref>

* M61A1

* M61A2

* [[GAU-19]] – General Electric, 12.7x997×99&nbsp;mm caliber

;'''Soviet Union/Russian Federation/CIS'''

* [[Glagolev-Shipunov-Gryazev GShG-7.62 machine gun]] – 7.62&nbsp;mm caliber

* [[Yakushev-Borzov YakB-12.7mm7 machine gun|Yakushev-Borzov YakB-12.7]] – 12.7&nbsp;mm caliber

* [[30 mm automatic cannon 2A42|Shipunov 2A42]] – 30&nbsp;mm caliber autocannon

* Anderton, David A. ''North American F-100 Super Sabre.''. Osprey Publishing, 1987. {{ISBN|978-0-85045-662-2}}.

* Campbell, John M. and Hill, Michael. ''Roll Call: Thud;: A Photographic Record of the F-105 Thunderchief.''. 1996, Schiffer Publishing. {{ISBN|0-7643-0062-8}}.

* Davies, Peter E. ''U.S. Air Force F-4 Phantom II MiG Killers 1965–68.''. Osprey Combat Aircraft #45, 2004, Osprey Publishing, UK. {{ISBN|1-84176-656-9}}.

* Davies, Peter E. ''USAF F-4 Phantom II MiG Killers 1972–73.''. Osprey Combat Aircraft 55 (2005). {{ISBN|1-84176-657-7}}.

* Hobson, Chris. ''Vietnam Air Losses, United States Air Force, Navy and Marine Corps Fixed-Wing Aircraft Losses in Southeast Asia 1961–1973.''. (2001) Midland Publishing. {{ISBN|1-85780-115-6}}.

* McCarthy Jr., Donald J. Jr. ''MiG Killers, A Chronology of U.S. Air Victories in the Vietnam War 1965–1973''. Specialty Press; 2009 {{ISBN|978-1-58007-136-9}}.

* Michel III, Marshall L. ''Clashes, Air Combat Over North Vietnam 1965–1972.''. Naval Institute Press; 1997. {{ISBN|978-1-59114-519-6}}.

* Toperczer, Istvan. ''MiG-17 and MiG-19 Units of the Vietnam War.''. Osprey Combat Aircraft #25, 2008 2nd ed. {{ISBN|978-1-84176-162-6}}.

* {{cite web |url = http://tri.army.mil/lc/cs/csa/aagatlin.htm#M61 |title = Evolution of the M61 Vulcan Gatling Gun |publisher = Army |url-status = dead |archive-url = https://web.archive.org/web/20080921095536/http://tri.army.mil/LC/CS/csa/aagatlin.htm#M61 |archive-date = 21 September 2008 }}.

* {{cite web |url = http://www.f-16.net/f-16_armament_article5.html |title = M61 A1 Vulcan – 20&nbsp;mm Gatling gun system |publisher = F-16}}.

* {{cite web |url = http://www.fas.org/man/dod-101/sys/ac/equip/m61.htm |title = M61 $| type = database item |publisher = Federation of American Scientists}}.

[[Category:Weapons and ammunition introduced in 195920x102mm]]