Editing Cannon (section)

===20th and 21st centuries===
[[File:Bundesarchiv DVM 10 Bild-23-61-35, Vergleich Geschützanzahl 1888-1913.jpg|thumb|Comparison of 1888 and 1913 German cannon]]
Cannons in the 20th and 21st centuries are usually divided into sub-categories and given separate names. Some of the most widely used types of modern cannon are howitzers, mortars, guns, and autocannon, although a few very [[large-calibre artillery|large-calibre cannon]], custom-designed, have also been constructed. [[Nuclear artillery]] was experimented with, but was abandoned as impractical.<ref>{{cite web|title=Nuclear artillery|url=http://www.nv.doe.gov/library/films/film.aspx?ID=1|access-date=26 May 2008|publisher=[[United States Department of Energy]]|url-status=dead|archive-url=https://web.archive.org/web/20080507020233/http://www.nv.doe.gov/library/films/film.aspx?ID=1|archive-date=7 May 2008}}</ref> Modern artillery is used in a variety of roles, depending on its type. According to [[NATO]], the general role of artillery is to provide fire support, which is defined as "the application of fire, coordinated with the manoeuvre of forces to destroy, neutralize, or suppress the enemy".<ref>{{cite book|title=AAP-6 NATO Glossary of Terms and Definitions|year=2007|publisher=[[North Atlantic Treaty Organization]]|access-date=26 May 2008|url=http://www.nato.int/docu/stanag/aap006/aap-6-2007.pdf|page=113|archive-date=14 May 2007|archive-url=https://web.archive.org/web/20070514133410/http://www.nato.int/docu/stanag/aap006/aap-6-2007.pdf|url-status=live}}</ref>

When referring to cannons, the term ''gun'' is often used incorrectly. In military usage, a gun is a cannon with a high muzzle velocity and a [[indirect fire|flat trajectory]], useful for hitting the sides of targets such as walls,<ref name = "mutuur"/> as opposed to howitzers or mortars, which have lower muzzle velocities, and fire indirectly, lobbing shells up and over obstacles to hit the target from above.<ref>{{cite dictionary|url=http://www.merriam-webster.com/dictionary/Howitzer|title=howitzer|access-date=26 May 2008|publisher=[[Merriam-Webster's Dictionary]]|archive-date=21 April 2009|archive-url=https://web.archive.org/web/20090421200515/http://www.merriam-webster.com/dictionary/howitzer|url-status=live}}</ref><ref>{{cite dictionary|url=http://www.merriam-webster.com/dictionary/Mortar|title=mortar|access-date=26 May 2008|publisher=[[Merriam-Webster's Dictionary]]|archive-date=4 September 2008|archive-url=https://web.archive.org/web/20080904220612/http://www.merriam-webster.com/dictionary/mortar|url-status=live}}</ref>

[[File:British 39th Siege Battery RGA Somme 1916.jpg|thumb|[[Royal Artillery]] [[howitzer]]s at the [[First day on the Somme|Battle of the Somme]]]]

By the early 20th century, [[infantry weapon]]s had become more powerful, forcing most artillery away from the front lines. Despite the change to [[indirect fire]], cannons proved highly effective during [[World War I]], directly or indirectly causing over 75% of casualties.<ref>Manucy, p. 20.</ref> The onset of [[trench warfare]] after the first few months of World War I greatly increased the demand for howitzers, as they were more suited to hitting targets in trenches. Furthermore, their shells carried more explosives than those of guns, and caused considerably less barrel wear. The German army had the advantage here as they began the war with many more howitzers than the French.<ref>{{cite book|first=Bruce I.|last=Gudmundsson|title=On Artillery|publisher=[[Greenwood Publishing Group]]|isbn=978-0-275-94047-8|year=1993|url=https://books.google.com/books?id=O_-0w2WUDd0C|page=43|access-date=25 September 2017|archive-date=20 October 2021|archive-url=https://web.archive.org/web/20211020080028/https://books.google.com/books?id=O_-0w2WUDd0C|url-status=live}}</ref> World War I also saw the use of the [[Paris Gun]], the longest-ranged gun ever fired. This {{convert|200|mm|in|0|adj=on|abbr=on}} calibre gun was used by the Germans against Paris and could hit targets more than {{convert|122|km|mi|abbr=on}} away.<ref>Young, p. 113.</ref>

The Second World War sparked new developments in cannon technology. Among them were [[sabot (firearms)|sabot rounds]], hollow-charge projectiles, and [[proximity fuse]]s, all of which increased the effectiveness of cannon against specific targets.<ref>{{cite book|last=McCamley|first=Nicholas J.|title=Disasters Underground|publisher=Pen & Sword Military|year=2004|isbn=978-1-84415-022-9}}</ref> The proximity fuse emerged on the battlefields of Europe in late December 1944.<ref>{{cite web|url=http://www.history.navy.mil/faqs/faq96-1.htm |title=Radio Proximity (VT) Fuzes |access-date=26 May 2008 |date=20 March 2000 |url-status=dead |archive-url=https://web.archive.org/web/20140209105150/http://www.history.navy.mil/faqs/faq96-1.htm |archive-date=9 February 2014 }}</ref> Used to great effect in [[anti-aircraft]] projectiles, proximity fuses were fielded in both the [[European Theater of Operations|European]] and [[Asiatic-Pacific Theater|Pacific]] Theatres of Operations; they were particularly useful against [[V-1 flying bomb]]s and [[kamikaze]] planes. Although widely used in naval warfare, and in anti-air guns, both the British and Americans feared unexploded proximity fuses would be reverse engineered, leading to them limiting their use in continental battles. During the [[Battle of the Bulge]], however, the fuses became known as the American artillery's "Christmas present" for the German army because of their effectiveness against German personnel in the open, when they frequently dispersed attacks.<ref>{{cite web|publisher=[[Smithsonian Institution]]|title=Variable Time Fuse Contributed to the Victory of United Nations|year=2007|access-date=5 October 2007|url=http://scienceservice.si.edu/pages/102001.htm|archive-date=13 October 2007|archive-url=https://web.archive.org/web/20071013124547/http://scienceservice.si.edu/pages/102001.htm|url-status=live}}</ref> [[Anti-tank gun]]s were also tremendously improved during the war: in 1939, the British used primarily [[Ordnance QF 2 pounder|2 pounder]] and [[Ordnance QF 6 pounder|6 pounder]] guns. By the end of the war, [[Ordnance QF 17 pounder|17 pounders]] had proven much more effective against German tanks, and 32 pounders had entered development.<ref name="Anti-tank guns">{{cite book|url=https://books.google.com/books?id=4IYXxrcx1_0C|title=World War II: A Visual Encyclopedia|last=Keegan|first=John|publisher=Sterling|year=2000|isbn=978-1-85585-878-7|page=29}}{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref>{{cite web|url=http://www.avalanchepress.com/BritainsAntiTankGuns.php|title=British Anti-Tank Guns|publisher=[[Avalanche Press]]|last=Rahman|first=Jason|date=November 2007|access-date=26 May 2008|archive-date=13 May 2008|archive-url=https://web.archive.org/web/20080513024413/http://www.avalanchepress.com/BritainsAntiTankGuns.php|url-status=live}}</ref> Meanwhile, German tanks were continuously upgraded with better [[tank gun|main guns]], in addition to other improvements. For example, the [[Panzer III]] was originally designed with a 37&nbsp;mm gun, but was [[mass production|mass-produced]] with a 50&nbsp;mm cannon.<ref name="German Tanks of World War II in Color">{{cite book|url=https://books.google.com/books?id=DZwQkZr0VrQC|title=German Tanks of World War II in Color|access-date=26 May 2008|year=2000|publisher=Zenith Imprint|page=46|last=Green|first=Michael|author2=Thomas Anderson|author3=Frank Schulz|isbn=978-0-7603-0671-0|archive-date=20 October 2021|archive-url=https://web.archive.org/web/20211020080025/https://books.google.com/books?id=DZwQkZr0VrQC|url-status=live}}</ref> To counter the threat of the Russian [[T-34]]s, another, more powerful 50&nbsp;mm gun was introduced,<ref name="German Tanks of World War II in Color"/> only to give way to a larger 75&nbsp;mm cannon, which was in a fixed mount as the [[Sturmgeschütz III|StuG III]], the most-produced German World War II armoured fighting vehicle of any type.<ref>Green, p. 47.</ref> Despite the improved guns, production of the Panzer III was ended in 1943, as the tank still could not match the T-34, and was replaced by the [[Panzer IV]] and [[Panther tank]]s.<ref>{{cite book|url=https://books.google.com/books?id=Xa6HLAhSzBAC|title=Kursk 1943: A Statistical Analysis|publisher=[[Routledge]]|year=2000|last=Zetterling|first=Niklas|author2=Anders Frankson|isbn=978-0-7146-5052-4|page=63|access-date=25 September 2017|archive-date=20 October 2021|archive-url=https://web.archive.org/web/20211020080022/https://books.google.com/books?id=Xa6HLAhSzBAC|url-status=live}}</ref> In 1944, the [[8.8 cm KwK 43|8.8&nbsp;cm KwK 43]] and many variations, entered service with the [[Wehrmacht]], and was used as both a tank main gun, and as the [[PaK 43]] anti-tank gun.<ref>{{cite book|title=German Early War Armored Fighting Vehicles|last=Bradford|first=George|year=2007|publisher=Stackpole Books|location=[[Mechanicsburg, Pennsylvania]]|page=3|isbn=978-0-8117-3341-0}}</ref><ref>{{cite book|title=The Mediterranean and Middle East|last=Playfair|first=Ian S. O.|author2=T. P. Gleave|publisher=[[HMSO]]|isbn=978-0-11-630946-4|page=257|year=1987}}</ref> One of the most powerful guns to see service in World War II, it was capable of destroying any [[Allies of World War II|Allied]] tank at very long ranges.<ref>{{cite book|url=https://books.google.com/books?id=LwqhCwNAjSYC|access-date=26 May 2008|title=Panzerkrieg: The Rise and Fall of Hitler's Tank Divisions|last=McCarthy|first=Peter|author2=Mike Syron|year=2003|publisher=[[Carroll & Graf Publishers]]|page=239|isbn=978-0-7867-1264-9|archive-date=20 October 2021|archive-url=https://web.archive.org/web/20211020080029/https://books.google.com/books?id=LwqhCwNAjSYC|url-status=live}}</ref><ref>{{cite book|url=https://books.google.com/books?id=-PXQYVjbp6MC|title=Tank Tactics: From Normandy to Lorraine|access-date=26 May 2008|page=115|last=Jarymowycz|first=Roman Johann|year=2001|publisher=Lynne Rienner Publishers|isbn=978-1-55587-950-1|archive-date=20 October 2021|archive-url=https://web.archive.org/web/20211020080038/https://books.google.com/books?id=-PXQYVjbp6MC|url-status=live}}</ref>

[[File:Uss iowa bb-61 pr.jpg|thumb|right|{{USS|Iowa|BB-61|6}} firing her {{convert|16|in|cm|0|abbr=on}} guns]]
Despite being designed to fire at trajectories with a steep angle of descent, howitzers can be fired [[direct fire|directly]], as was done by the [[11th Marine Regiment#Korean War|11th Marine Regiment]] at the [[Battle of Chosin Reservoir]], during the [[Korean War]]. Two [[Artillery battery#Modern battery organization|field batteries]] fired directly upon a [[battalion]] of Chinese infantry; the Marines were forced to brace themselves against their howitzers, as they had no time to dig them in. The Chinese infantry took heavy casualties, and were forced to retreat.<ref>{{cite book|last=Russ|first=Martin|year=1999|title=Breakout: The Chosin Reservoir Campaign, Korea 1950|pages=383–384|publisher=[[Penguin Books]]|isbn=978-0-14-029259-6}}</ref>

The tendency to create larger calibre cannons during the World Wars has reversed since. The [[United States Army]], for example, sought a lighter, more versatile howitzer, to replace their aging pieces. As it could be towed, the M198 was selected to be the successor to the World War II–era cannons used at the time, and entered service in 1979.<ref name="M198 Info">{{cite web|url=http://tech.military.com/equipment/view/146534/m198-155mm-towed-howitzer.html|title=M198 information|access-date=26 May 2008|publisher=Military.com|url-status=dead|archive-url=https://web.archive.org/web/20080605002819/http://tech.military.com/equipment/view/146534/m198-155mm-towed-howitzer.html|archive-date=5 June 2008}}</ref> Still in use today, the M198 is, in turn, being slowly replaced by the [[M777 howitzer|M777]] Ultralightweight howitzer, which weighs nearly half as much and can be more easily moved. Although land-based artillery such as the M198 are powerful, long-ranged, and accurate, naval guns have not been neglected, despite being much smaller than in the past, and, in some cases, having been replaced by [[cruise missile]]s.<ref name="Cruise missile">{{cite web|url= http://www.nationaldefensemagazine.org/issues/2001/Mar/Naval_Guns.htm|title=Affordable precision| work = National Defense Magazine|access-date=26 May 2008 |archive-url = https://web.archive.org/web/20061008233620/http://www.nationaldefensemagazine.org/issues/2001/Mar/Naval_Guns.htm |archive-date = 8 October 2006}}</ref> However, the {{sclass|Zumwalt|destroyer|1}}'s planned armament included the [[Advanced Gun System]] (AGS), a pair of 155&nbsp;mm guns, which fire the [[Long Range Land-Attack Projectile]]. The warhead, which weighed {{convert |24|lb|kg}}, had a [[Circular error probable|circular error of probability]] of {{convert|50|m|ft|abbr=on}}, and was mounted on a rocket, to increase the effective range to {{convert|100|nmi|km|abbr=on}}, further than that of the Paris Gun. The AGS's barrels would be water-cooled, and fire 10 rounds per minute, per gun.  The combined firepower from both turrets would give a ''Zumwalt''-class destroyer the firepower equivalent to 12 conventional M198 howitzers.<ref>{{cite web |last1=Lacch |first1=Franco |title=Scandalo Zumwalt: cancellata la torretta da 155 millimetri, un singolo proiettile costa 800 mila dollari |url=https://www.difesaonline.it/mondo-militare/scandalo-zumwalt-cancellata-la-torretta-da-155-millimetri-un-singolo-proiettile-costa |website=Difesa Online |access-date=17 September 2023 |language=it |date=7 November 2016}}</ref> The reason for the re-integration of cannons as a main armament in United States Navy ships was because satellite-guided munitions fired from a gun would be less expensive than a cruise missile but have a similar guidance capability.<ref name="Cruise missile"/>

====Autocannon====
{{Main|Autocannon}}
[[File:USSVixenMaximMachineGun.1898.ws.jpg|thumb|right|A large bore Maxim on {{USS|Vixen|PY-4|6}} c. 1898]]

Autocannons have an automatic firing mode, similar to that of a machine gun. They have mechanisms to automatically load their ammunition, and therefore have a higher rate of fire than artillery, often approaching, or, in the case of [[rotary cannon|rotary autocannons]], even surpassing the firing rate of a machine gun.<ref name="Autocannon Rate of Fire"/> While there is no minimum bore for autocannons, they are generally larger than machine guns, typically {{convert|20|mm|abbr=on}} or greater since World War II and are usually capable of using explosive ammunition even if it is not always used. Machine guns in contrast are usually too small to use explosive ammunition;<ref name= "dictionary definition">{{Cite dictionary |title=cannon |url=http://www.merriam-webster.com/dictionary/cannon |dictionary=Merriam-Webster.com Dictionary |publisher=Merriam Webster |archive-date=20 September 2011 |archive-url=https://web.archive.org/web/20110920111236/http://www.merriam-webster.com/dictionary/cannon |url-status=live |access-date=17 September 2011}}</ref> such ammunition is additionally banned in international conflict for the parties to the [[Saint Petersburg Declaration of 1868]].

Most nations use rapid-fire cannon on light vehicles, replacing a more powerful, but heavier, tank gun. A typical autocannon is the [[25 mm caliber|25&nbsp;mm]] "[[M242 Bushmaster|Bushmaster]]" [[chain gun]], mounted on the [[LAV-25]] and [[M2 Bradley]] [[Infantry fighting vehicle|armoured vehicles]]. Autocannons may be capable of a very high rate of fire, but ammunition is heavy and bulky, limiting the amount carried. For this reason, both the 25&nbsp;mm Bushmaster and the 30&nbsp;mm [[RARDEN]] are deliberately designed with relatively low rates of fire. The typical rate of fire for a modern autocannon ranges from 90 to 1,800 rounds per minute. Systems with multiple barrels, such as a rotary autocannon, can have rates of fire of several thousand rounds per minute. The fastest of these is the [[Gryazev-Shipunov GSh-6-23|GSh-6-23]], which has a rate of fire of over 10,000&nbsp;rounds per minute.<ref name="Autocannon Rate of Fire">{{Cite book |last=Williams |first=Anthony G. |year=2000 |title=Rapid Fire: The Development of Automatic Cannon, Heavy Machine Guns and Their Ammunition for Armies, Navies and Air Forces |location=Shrewsbury, UK |publisher=Airlife |page=241 |isbn=978-1-84037-435-3 |oclc=50940059}}</ref>

Autocannons are often found in aircraft, where they replaced machine guns and as shipboard anti-aircraft weapons, as they provide greater destructive power than machine guns.<ref name="Aircraft Cannon"/>

====Aircraft use====
{{main|Aircraft artillery}}

The first documented installation of a cannon firing [[explosive shell]]s on an aircraft was on the Voisin Canon in 1911, displayed at the Paris Exposition that year. By World War I, all of the major powers were experimenting with aircraft-mounted cannons; however, their low rate of fire and great size and weight precluded any of them from being anything other than experimental. The most successful (or least unsuccessful) was the SPAD 12 Ca.1 with a single 37&nbsp;mm Puteaux mounted to fire between the cylinder banks and through the propeller boss of the aircraft's Hispano-Suiza 8C. The pilot (by necessity an ace) had to manually reload each round.<ref name="Early Aircraft Armament">{{cite book | last = Woodman | first = Harry | author-link = Harry Woodman | title = Early Aircraft Armament – The Aircraft and the Gun up to 1918 | publisher = [[Arms and Armour Press]] | year = 1989 | isbn = 978-0-85368-990-4}}</ref>

The first autocannon were developed during World War I as anti-aircraft guns, and one of these, the [[Coventry Ordnance Works]] "[[COW 37 mm gun]]", was installed in an aircraft. However, the war ended before it could be given a field trial, and it never became standard equipment in a production aircraft. Later trials had it fixed at a steep angle upwards in both the [[Vickers Type 161]] and the [[Westland C.O.W. Gun Fighter]], an idea that would return later.

During this period autocannons became available and several fighters of the German {{lang|de|[[Luftwaffe]]}} and the [[Imperial Japanese Navy Air Service]] were fitted with 20&nbsp;mm cannons. They continued to be installed as an adjunct to machine guns rather than as a replacement, as the rate of fire was still too low and the complete installation too heavy. There was a some debate in the RAF as to whether the greater number of possible rounds being fired from a machine gun, or a smaller number of explosive rounds from a cannon was preferable. Improvements during the war in regards to rate of fire allowed the cannon to displace the machine gun almost entirely.<ref name="Aircraft Cannon"/> The cannon was more effective against armour so they were increasingly used during the course of World War II, and newer fighters such as the [[Hawker Tempest]] usually carried two or four instead of the six [[M2 Browning|.50 Browning machine guns]] for US aircraft or eight to twelve [[M1919 Browning machine gun]]s on earlier British aircraft. The [[Hispano-Suiza HS.404]], [[Oerlikon 20 mm cannon|Oerlikon 20&nbsp;mm cannon]], [[MG FF cannon|MG FF]], and their numerous variants became among the most widely used autocannon in the war. Cannons, as with machine guns, were either fixed to fire forwards (mounted in the wings, in the nose or fuselage, or in a [[pannier]] under either), or mounted in [[gun turret]]s on heavier aircraft. Both the Germans and Japanese mounted cannons to fire upwards and forwards for use against heavy bombers, with the Germans calling guns so-installed {{lang|de|[[Schräge Musik]]}}, derived from a German colloquialism for jazz music—{{lang|de|schräg}} means "off-key".

Preceding the [[Vietnam War]] the high speeds aircraft were attaining and availability of missiles led to a move to omit cannon due to the belief that they would be useless in a [[dogfight]], but combat experience during the Vietnam War showed conclusively that, despite advances in missiles, there was still a need for cannon. Nearly all modern [[fighter aircraft]] are armed with an autocannon, and they are also commonly found on [[ground-attack aircraft]]. One of the most powerful examples is the 30mm GAU-8/A Avenger Gatling-type rotary cannon mounted on the [[Fairchild Republic A-10 Thunderbolt II]].<ref name="Aircraft Cannon" /><ref>{{cite web|url= https://www.442fw.afrc.af.mil/News/story/id/123055695/ |title=GAU-8/A |publisher=442nd Fighter Wing |access-date=26 May 2008 |url-status=live |archive-url= https://web.archive.org/web/20110719063934/http://www.442fw.afrc.af.mil/news/story.asp?id=123055695 |archive-date=19 July 2011 }}</ref> The [[Lockheed AC-130]] gunship (a converted transport) can carry a 105&nbsp;mm howitzer as well as a variety of autocannons ranging up to 40&nbsp;mm.<ref>{{cite web|url= http://www.123exp-warfare.com/t/03804237449/|title=Information on the GAU-8/A| work =The Language of Weaponry|access-date=26 May 2008|archive-url= https://web.archive.org/web/20090619223736/http://www.123exp-warfare.com/t/03804237449/ |archive-date=19 June 2009|url-status=usurped}}</ref> Both are used in the [[close air support]] role.

<gallery>
File:Westland C.O.W. Gun Fighter.jpg | [[Westland C.O.W. Gun Fighter]] with 37&nbsp;mm C.O.W. gun mounted to fire upwards
File:Supermarine Spitfire Mk XVI.jpg| [[Supermarine Spitfire]] with 20&nbsp;mm cannon protruding from the leading edge of the wing
File:GSh-23 on MiG-23.jpg | [[GSh-23]] autocannon mounted on the underside of a [[Mikoyan-Gurevich MiG-23]]
File:GAU-8 in A-10.jpg | The [[GAU-8/A Avenger]] rotary cannon, mounted in a [[Fairchild A-10 Thunderbolt II]]
</gallery>