Editing M61 Vulcan (section)

==Applications and first combat use==
[[File:F-104 Waffenschacht.jpg|thumb|Gun installation on West German [[F-104]]]]

The Vulcan was first used in aerial combat on 4 April 1965, when four [[North Vietnam]]ese [[Vietnam People's Air Force]] (VPAF) [[MiG-17]]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 leader 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 lieutenants Pham Giay, Le Minh Huan and Tran Nguyen Nam. 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 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 VPAF MiG flew in front of him after making its pass, Tracy opened fire on it.<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 cannons in a prominent fairing under the nose, well before the war ended (Navy Phantoms never received cannons, 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 |work=Air Force |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>

{| class="wikitable"
|+ Combat kills using the M61 Vulcan in the Vietnam War 1966–1972<ref>McCarthy Jr. pp. 148–157. Excludes combination air-to-air missile/gun kills.</ref>
|-
! Date/year
! Firing aircraft
! M61 Vulcan variant
! Aircraft downed
! USAF unit/comments
|-
|29 June 1966
|[[Republic F-105 Thunderchief|F-105D Thunderchief]]
|M61A1
|[[MiG-17]]
|[[421st Tactical Fighter Squadron]]<ref>McCarthy Jr. p. 38</ref>
|-
|18 August 1966
|F-105D
|M61A1
|MiG-17
|[[34th Fighter Squadron|34th TFS]]
|-
|21 September 1966
|F-105D
|M61A1
|MiG-17
|[[333d Fighter Squadron|333rd TFS]]
|-
|21 September 1966
|F-105D
|M61A1
|MiG-17
|[[431st Test and Evaluation Squadron|431st TFS]]
|-
|4 December 1966
|F-105D
|M61A1
|MiG-17
|[[469th Flying Training Squadron|469th TFS]]
|-
|1967
|F-105D/F-105F
|M61A1
|(5) MiG-17s
|333rd TFS
|-
|1967
|F-105D
|M61A1
|(8) MiG-17s
|354th TFS
|-
|1967
|F-105D/F-105F
|M61A1
|(4) MiG-17s
|357th TFS
|-
|1967
|F-4C Phantom II
|[[SUU-16]] gunpod
|(2) MiG-17s
|480th TFS
|-
|13 May 1967
|F-105D
|M61A1
|MiG-17
|44th TFS
|-
|3 June 1967
|F-105D
|M61A1
|MiG-17
|13th TFS: Captain Ralph Kuster<ref>Campbell & Hill p. 43/photo of his F-105 plate # 213</ref>
|-
|23 August 1967
|F-105D
|M61A1
|MiG-17
|34th TFS
|-
|24 October 1967
|F-4D
|[[SUU-23]] gunpod
|[[MiG-21]]
|433rd TFS
|-
|1967
|F-4D
|SUU-23
|(3) MiG-17s
|435th TFS
|-
|3 January 1968
|F-4D
|SUU-23
|MiG-17
|433rd TFS; pilot, Major B J Bogoslofski, [[Weapon systems officer|WSO]], Captain Richard L Huskey<ref>Davies, Osprey #45, p. 86</ref>
|-
|14 February 1968
|F-4D
|SUU-23
|MiG-17
|555th TFS
|-
|1972
|F-4E
|M61A1
|(3) MiG-21s
|35th TFS; the F4E was the first Phantom II to enter the war with an internal Vulcan gun.<ref>Michel III pp. 181, 267</ref>
|-
|2 June 1972
|F-4E
|M61A1
|[[MiG-19]]
|58th TFS; first 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>
|-
|9 September 1972
|F-4E
|M61A1
|MiG-21
|555th TFS
|-
|15 October 1972
|F-4E
|M61A1
|MiG-21
|307th TFS
|-
! colspan="5" |
|-
!Total MiG-17s
|colspan="4" |32
|-
!Total MiG-19s
|colspan="4" |1
|-
!Total MiG-21s
|colspan="4" |6
|-
!Total
|colspan="4" |39
|}
[[File:M163 VADS.JPEG|thumb|right|An M61 mounted on a US Army [[M163 VADS|M163]] armored vehicle]]

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 />

Two [[gun pod]] versions, the [[U.S. aircraft gun pods|SUU-16/A]] (also designated M12 by the US Army) and improved [[U.S. aircraft gun pods|SUU-23/A]] (US Army M25), were developed in the 1960s, often used on gunless versions of the F-4. The SUU-16/A uses the electric M61A1 with a [[ram-air turbine]] to power the motor. This proved to cause serious [[Drag (physics)|aerodynamic drag]] at higher speeds, while speeds under {{convert|400|mph|km/h|order=flip}} did not provide enough airflow for the maximum rate of fire.<ref>Gervasi, 1984. p. 239</ref>

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]] as used 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 universal turret]] 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>

The M61 is also the basis of the US Navy [[Phalanx CIWS|Mk 15 Phalanx]] [[close-in weapon system]] and the [[M163 VADS]] Vulcan Air Defense System, using the M168 variant.<ref>{{Cite web |url=http://weaponsystems.net/weaponsystem/EE03%20-%20M163%20Vulcan.html |title=M163 Vulcan |access-date=23 May 2019 |archive-url=https://web.archive.org/web/20170112061408/http://www.weaponsystems.net/weaponsystem/EE03%20-%20M163%20Vulcan.html |archive-date=12 January 2017 |url-status=live }}</ref>

On 13 December 2024, the [[Ukrainian Air Force]] claimed a F-16 shot down 6 Russian cruise missiles. Two were shot down with “medium-range missiles”, another two with “short-range missiles” and finally two with the M61 Vulcan 20 mm cannon. The pilot wasn’t identified for security reasons but said: "A few bursts from the cannon — and an explosion... then another one! 'A secondary detonation,' I thought, but, as it turned out, there were two missiles," <ref>{{Cite news |date=2024-12-13 |title= In historic record, Ukrainian F-16 pilot downs 6 cruise missiles in single mission, Air Force claims |url= https://kyivindependent.com/ukrainian-f-16-pilot-downs-6-cruise-missiles/ |work=The Kyiv Independent| author= Martin Fornusek |language=en}}</ref>