View source for AT4

{{About|the unguided anti-tank weapon|the Russian guided anti-tank missile|AT-4 Spigot}}
{{Redirect|M136}}

{{Infobox Weapon
|name= AT4, AT4 CS, AT4-CS, AT-4CS
|image= [[File:AT4 rocket launcher.jpg|300px]]
|caption=Firing an AT-4 produces a large back blast, a significant problem when operating the weapon in urban environments.
|origin={{flagcountry|Sweden}}
|type= [[Anti-tank weapon]]
<!-- Type selection -->
|is_ranged=yes
|is_explosive=yes
<!-- Service history -->
|service= 
|used_by=See ''[[AT4#Users|Users]]''
|wars= <li>[[United States invasion of Panama|U.S. invasion of Panama]]<ref name="amnestysweden">http://www.svenskafreds.se/english/vapenexport.pdf</ref><li> [[War in Afghanistan (2001-present)|Afghanistan War]]<ref name="amnestysweden"/><li> [[Iraq War]]<ref name="amnestysweden"/>
<!-- Production history -->
|designer= 
|design_date=
|manufacturer= [[Saab Bofors Dynamics]]
|unit_cost= U.S. $1,480.64 <ref>[http://www.fas.org/man/dod-101/sys/land/at4.htm M136 AT4<!-- Bot generated title -->]</ref>
|production_date=
|number= 600,000+ <ref name="kemp2006">Kemp, Ian. "The law gets tougher: the shoulder-launched light anti-armour weapon has evolved to become a multipurpose assault weapon much in demand for asymmetric warfare". Armada International (April-May 2006). ISSN 0252-9793.</ref>
|variants= AT-4 CS
<!-- General specifications -->
|weight= 6.7 [[kilogram|kg]] (14.8 [[pound (mass)|lb]]) <ref name="mcmanners2003">McManners, Hugh (2003). ''Ultimate Special Forces''. DK Publishing, Inc. ISBN 0-7894-9973-6.</ref>
|length= 102 [[centimetre|cm]] (40 [[inch (length)|in]]) <ref name="mcmanners2003"/>
|part_length= 
|width=
|height=
|crew=
<!-- Ranged weapon specifications --> 
|cartridge= 
|caliber= 84 [[millimetre|mm]]
|action= 
|rate= 
|velocity= 290 [[metres per second|m/s]] (950 [[feet per second|ft/s]]) <ref name="owen2007">{{cite web |url=http://www.asianmilitaryreview.com/upload/200712031855161.pdf |title=Light Anti-Armour Weapons: Anti-Everything? |author=Owen, William F. |year=2007 |publisher=http://asianmilitaryreview.com - Asian Military Review |accessdate=2010-05-12}}</ref>
|range= 300 [[metre|m]] (point target) <ref name="mcmanners2003"/>
|max_range= 500 m (area target)<br/>2100 m (maximum)
|feed= 
|sights= Iron sights, optional night vision unit
<!-- Explosive specifications --> 
|diameter= 
|filling=[[Octogen]]/[[TNT]]
|filling_weight= 440 g HE (HEAT round)
|detonation=
|yield=
}}
{{externalimage
|topic=Prototype AT4 Sweden tested 1981/82
|align=right
|image1=[http://i16.photobucket.com/albums/b24/hybenamon/LAND/INFANTRY/AT4%20and%20M136/AT4-Early-lo.jpg Early AT4 with Swedish Soldier]
|image2=[http://i16.photobucket.com/albums/b24/hybenamon/LAND/INFANTRY/AT4%20and%20M136/AT-EARLY-LauncherWarhead.jpg Early AT4 launcher and projectile]
}}

The '''AT4''' (also variously '''AT-4''', '''AT4 CS, AT4-CS''', or '''AT-4CS''')<ref>The designation AT-4 is an alpha-phonetic word play on the weapon's role (AT = "Anti-Tank") and [[calibre]] of 84 mm. Hewish, Mark, "FFV's Lightweight AT4, first of a new family of Swedish anti-armour weapons" ''International Defense Review'', May 1982, p. 70.</ref> is an 84-mm unguided, portable, single-shot recoilless smoothbore weapon built in [[Sweden]] by [[Saab Bofors Dynamics]] (previously Bofors Anti-Armour Systems). [[Saab]] has had considerable sales success with the AT4, making it one of the most common light [[Anti-tank warfare|anti-tank]] weapons in the world.

The designation "CS" represents "Confined Space" referring to the propellant charge being designed to operate effectively within buildings in an urban environment.<ref name="MC081118">Military Channel, "[[Weaponology]]" program, "[[Hand grenade|Grenade]]s through [[Rocket propelled grenade|RPGs]]"|note=(exact title unknown, didn't look in time)|, rebroadcast: 2008-11-18; Note: Documentary Program concluded that this weapon was the best recent technology in a long line of grenades, anti-armor and RPG weapons, part of "best" being cost per shot and ease of use. More sophisticated "missile" based systems have severe ''cost and "need-of-training" negative factors'' by comparison with this [[Bazooka]]-like system, ''"which any 'farm peasant can be trained to fire.'" (paraphrased conclusion)</ref> It is intended to give [[infantry]] units a means to destroy or disable [[armored vehicle]]s and [[fortification]]s, although it is not generally sufficient to defeat a modern [[Tank classification#Main battle tank|main battle tank]] (MBT). The launcher and projectile are manufactured prepacked and issued as a single unit of ammunition, rather than as a weapon system, with the launcher discarded after a single use.

==Development==
The AT4 is a development of the 74-mm [[Miniman antitank weapon|''Pansarskott m/68'']] <ref>''Pansarskott'' is a Swedish term that roughly translates to "Armour Shot."</ref> (Miniman), adopted by the [[Swedish Army]] in the late 1960s. Like the m/68, the AT4 was designed by Försvarets Fabriksverk (FFV) and manufactured at their facility at Zakrisdal, [[Karlstad]], [[Sweden]].  FFV began research in a replacement for the m/68 in 1976, deliberately designing an individual antiarmor weapon that would not be able to defeat the heavy armour protection of MBTs (main battle tanks) in frontal engagements, believing that to be counterproductive.  The AT4 was designed as a weapon to engage medium to light armored vehicles from any direction, MBTs from the sides or rear, and as an assault weapon against buildings and fortifications.  FFV also had the design goal of a weapon that was simple to use, rugged and was far more accurate than previous individual antiarmor weapons against moving targets.  Another key requirement was that the AT4 not only be able to penetrate armor, but also have a devastating [[beyond-armour effect]] after penetration.  FFV and the Swedish Army began the first evaluation firings of the prototype AT4s in the spring of 1981 with 100 tested by early 1982.<ref>''International Defense Review'', May 1982, p. 71.</ref>

Even before the AT4 had been adopted by Sweden, it was entered into a [[United States Army|U.S. Army]] competition for a new anti-tank weapon mandated by Congress in 1982 when the [[FGR-17 Viper]] failed as a replacement for the [[M72 LAW]]. Six weapons were tested in 1983 by the US Army: the British [[LAW 80]], the German [[Armbrust]], the French [[APILAS]], the Norwegian M72E4 (an upgraded M72 LAW), the U.S. Viper (for baseline comparison purposes) and the Swedish AT4.  The U.S. Army reported back to Congress in November 1983 that the FFV AT4 came the closest to meeting all the major requirements established to replace the M72 LAW,<ref>The French APILAS was the only tested weapon which had the maximum penetration to defeat the frontal armor of the new Russian T-72 MBT, but it was rejected due to its weight and size.</ref> with the Armbrust coming in second.<ref>The Armbrust, while an impressive weapon, with its almost total lack of launch signature that enabled it to be fired from enclosed spaces, was rejected due to higher cost and lack of effective range against moving targets.</ref>

Though very impressed with the simplicity and durability of the tested version of the AT4, the U.S. Army saw some room for improvement, specifically the addition of rear and front bumpers on the launch tube and changes to the sights and slings. After these changes, the AT4 was adopted by the U.S. Army as the ''Lightweight Multipurpose Weapon'' M136.<ref>the US Army had so much grief in the early 1980s from various committee members of the US Congress over the M72 LAW being officially referred to in manuals as a Light ANTITANK Weapon that they named the AT4 to made sure no member of Congress could question that again</ref> The Swedish army also recognized these improvements and subsequently adopted the Americanized version of the AT4 as the ''Pansarskott m/86'' (''Pskott m/86''), with the addition of a forward folding hand grip to help steady the AT4 when being aimed and fired.  The forward folding grip is the only difference between the AT4 adopted by Sweden and the U.S. Army version.

Due to the urban combat conditions that US military forces in the last several years have been facing regularly, the US Army Close Combat Systems manager in charge of purchases of the AT4, suspended orders for the standard version of the AT4, and are now ordering only the AT4 CS version.<ref>John Antal "Packing a Punch: America's Man-Portable Antitank Weapons" page 90 Military Technology 3/2010 ISSN 0722-3226</ref>

==Operation==
The AT4 may be compared to a less-expensive one-shot [[Carl Gustav recoilless rifle]].  The AT4 took many of its design features from the Carl Gustav, which operates on the principle of a [[recoilless weapon]], where the forward [[inertia]] of the [[projectile]] is balanced by the mass of [[propellant]] gases ejecting from the rear of the barrel. But unlike the Carl Gustav, which uses a heavier and more expensive steel tube with [[rifling]] <ref>Until the 1980s the Carl Gustav was constructed of high-alloy steel, but later versions used a thin steel liner containing the rifling, strengthened by a [[carbon fiber]] outer sleeve.</ref>, the disposable AT4 design greatly reduces manufacturing costs by using a reinforced smoothbore [[fiberglass]] outer tube.  Since recoilless weapons generate almost no [[recoil]], a relatively large projectile can be fired which would otherwise be impossible in a man-portable weapon.

In the system originally developed by FFV for the Carl Gustav, a plastic blowout plug is placed at the center rear of the shell casing containing the projectile and propellant, which itself is enclosed in the AT4 outer tube.  When the gases build up to the correct pressure level, the blowout plug disintegrates allowing the proper amount of gases to be vented to the rear, balancing the propellant gases pushing the projectile forward.

The AT4 uses a unique method developed earlier by FFV and adopted for the AT4: the spring-loaded firing rod is located down the side of the outer tube, with the [[firing pin]] at the rear side of the tube.  When released, the firing pin strikes a primer located in the side of the casing's rim.  Additionally, as the shell casing absorbs the majority of the firing stresses, the launch tube can be designed to be very lightweight as it does not have to contend with the extreme pressures found in traditional cannons.

The disadvantage of the recoilless design is that it creates a large "back blast" area behind the weapon which can cause severe burns and [[overpressure]] injuries both to friendly personnel in the vicinity of the user and sometimes to the users themselves, especially in confined spaces. The back blast may also reveal the user's position to the enemy. [[File:AT-4 live-fire.jpg|thumb|left|200px|A [[United States Marine Corps|U.S. Marine]] fires an AT-4 during live-fire training at Udairi Range in Kuwait, January 2008.]] 

The problem of back blast has been recently solved with the '''AT4-CS''' (Confined Space) version, specially designed for [[urban warfare]].  This version uses a saltwater countermass in the rear of the launcher to absorb the back blast; the resulting spray captures and dramatically slows down the pressure wave, allowing troops to fire from enclosed areas.

To fire, the gunner first removes the safety pin located at the rear of the tube, which unblocks the firing rod. He then takes a firing position ensuring that no one is present in the back blast area. If firing from the prone position (lying on his stomach) he must also place his legs well to the side to avoid burning himself. Then the gunner moves back the front and rear sight covers, allowing the sights to pop up into their firing positions. The AT4 sights are [[iron sight]]s and were originally developed for the cancelled Viper, and are similar in concept and use to those on assault rifles.<ref>FFV and the Swedish Army were so impressed by these sights that they adopted them for their AT4s; while adequate during the day, the original plastic sights were difficult to see at night or under low light conditions.</ref>  He then removes the first of two [[Safety (firearm)|safeties]] by moving the firing rod cocking lever (located on the left side) forward and then over the top to the right side.  The gunner takes aim, while at the same time holding down the red safety lever located in front of the cocking lever, and then fires by pressing forward the the red firing button with his right thumb. Both the red safety lever and firing button must be pressed down at the same time to fire the AT4.  The red firing button has resistance similar to the trigger pull of an assault rifle, so the gunner does not have to jab at the firing button which could throw his aim off.

After firing, the AT4 is discarded.  Unlike the heavier Carl Gustav, the AT4 outer tube is built only to take the stress of one firing; it is not reusable and can not be reloaded like the Carl Gustav.

Alternatively, the AT4 can mount an optical [[night sight]] on a removable fixture. In U.S. military use, the launcher can be fitted with the AN/PAQ-4C, AN/PEQ-2, or the AN/PAS-13 night sights.

The AT4 requires little training and is quite simple to use, making it suitable for general issue. However, as the cost of each launcher makes regular live-fire training very expensive, practice versions exist which are identical in operation but fire reloadable [[9x19mm Parabellum|9mm]] or [[20 mm caliber|20mm]] [[tracer ammunition]]. Both practice cartridges are unique to their respective weapons, with their trajectory matched to that of the live round. The 20mm version also  has a [[recoilless weapon]] effect with same high noise and back blast as the AT4 firing and is favored by the Swedish army because of the added realism of the back blast as compared to the "plonk" sound of the 9mm round (similar to the sound of a finger tapping on an empty can).
{{externalimage
|topic=AT4 version adopted by US as M136
|align=right
|image1=[http://i16.photobucket.com/albums/b24/hybenamon/LAND/INFANTRY/AT4%20and%20M136/AT4showingammunitionandprojectile.jpg AT4 launcher shown with ammunition and HEAT projectile]
|image2=[http://i16.photobucket.com/albums/b24/hybenamon/LAND/INFANTRY/AT4%20and%20M136/AT5Cutawayshowingammuntioninstalled.jpg AT4 cutaway illustration showing ammunition installed]
|image3=[http://ordatamines.maic.jmu.edu/images/D3646UC1.jpg Cutaway of AT4 HEAT warhead - note trumpet shaped liner and focus ring at front of liner]
|image4=[http://i16.photobucket.com/albums/b24/hybenamon/LAND/INFANTRY/AT4%20and%20M136/ATFrontSight.jpg AT4 front sight extended]
|image5=[http://i16.photobucket.com/albums/b24/hybenamon/LAND/INFANTRY/AT4%20and%20M136/AT4RearSight.jpg AT4 rear sight extended]
|image6=[http://i16.photobucket.com/albums/b24/hybenamon/LAND/INFANTRY/AT4%20and%20M136/AT4cocksafetypushsafetyandfirebutto.jpg AT4 cock safety, press finger safety, and thumb firing button]
}}

==Specifications==
*Length: 101.6&nbsp;cm (40 in.)
*Weight: 6.7&nbsp;kg (14.77 pounds)
*Bore diameter: 84&nbsp;mm
*Maximum effective range: 300 metres (984.3&nbsp;feet), although it has been used in excess of 500 meters for area fire.
*Penetration: 400&nbsp;mm of [[rolled homogeneous armour]] (RHA) (also see below)
*Time of flight (to 250 metres): less than 1 second
*Muzzle velocity: 285 metres (950&nbsp;feet) per second
*[[Operating temperature]]: -40 to +60°C (-40 to +140°F)
*Ammunition: Fin-stabilized projectile with [[HEAT]] warhead

==Projectiles==
There are several different projectiles for the AT4. Note that since the AT4 is a one-shot weapon, these projectiles are preloaded into the launcher tubes. 

[[File:AT4 image.jpg|thumb|right|300px|AT4 launcher and projectile.]]

;HEDP 502 (High Explosive Dual Purpose)<ref>the complete disposable launcher and HEDP projectile is referred to by the manufacture in brochures as the LMAW - ie ''light multipurpose-assault weapon'' -- see external links for link on early photos and press releases for further information on brochure</ref>
:For use against [[bunker]]s, buildings, enemy personnel in the open and light armor. The projectile can be set to detonate on impact or with a slight delayed detonation.  The heavier nose cap allows the HEDP projectile to penetrate light walls or windows and then explode, or "skipped" off the ground for an air-burst.  For use against light armor, there is a smaller cone HEAT warhead with 150 mm of penetration against RHA.

;HP (High Penetration)
:Extra high penetration ability (up to 500 to 600 mm of RHA.)

;AST (Anti Structure Tandem-warheads)
:Designed for urban warfare where a projectile heavier than the HEDP AT4 is needed. Two warheads, first one a HEAT with a shallow cone resulting in less penetration but a wider hole, and a second follow through high-blast warhead.  It has two settings: one for destroying bunkers and one for ''mouse holing'' a building wall for combat entry.<ref>[http://www.youtube.com/watch?v=Q3xsMqHu56g&feature=related 2008 SAAB video on AT4 versions including new multipurpose warhead for urban combat]</ref> 

{{multiple image
|align= right
|width= 130
|image1= AT4 HEAT and AT8 Bunker Busting Projectile.jpg 
|width1= 
|caption1= Complete AT4 HEAT antitank round (which is preloaded in AT4) and AT8 bunker busting warhead.
|image2= FFV 502 HEPD LMAW projectile.jpg
|width2= 
|caption2= 502 HEDP projectile for LMAW.
}}
;HEAT (High Explosive Anti Tank)
:The AT4 HEAT can penetrate up to 420 mm of [[Rolled homogeneous armour|RHA]] with ''[[beyond-armour effect]]''.<ref>History Channel, ''Lock N' Load With R. Lee Ermey'', ''Rockets'' episode, aired October 23, 2009.</ref>

;AT8 (Bunker Busting)
:A version of the AT4 where the standard HEAT projectile is replaced with the bunker busting warhead developed for the [[Shoulder-launched Multipurpose Assault Weapon|SMAW]]. No orders placed.<ref>Jane's Infantry Weapons 1995-96 page 220.  The reference refers to Allaint Techsystems as the manufacture, but they soon after were acquired by Honeywell.  The [[M141 Bunker Defeat Munition|SMAW-D]] offered by Talley was chosen for the US Army program that the AT-4 entered.  See external images at the SMAW-D link for a brochure on the AT-8</ref>

;AT12 (130mm Frontal Engagement Version)
:In the early 1990s, there were tests of a [[tandem charge]] 130-mm version (Bofors AT 12) that would be able to penetrate the front armor of any modern (MBT). However, the project was canceled due to the dissolution of the [[Soviet Union]] and cuts in Western defense budgets.

==Users==
<!--READ FIRST: This section is for cited entries only. Please do not add entries into this list without a citation from a reliable source. All entries without a citation will be removed.-->

*{{flag|Brazil}}<ref name="jones2009">Jones, Richard D. ''Jane's Infantry Weapons 2009/2010''. Jane's Information Group; 35 edition (January 27, 2009). ISBN 978-0-7106-2869-5.</ref>
*{{flag|Croatia}}<ref name="jones2009"/>
*{{flag|Denmark}}: Designated ''PVV M/95'' (''P''anser''v''ærns''v''åben ''M''odel 19''95'').<ref>The World Defence Almanac 2000-01 page 93 ISSN 0722-3226</ref>
*{{flag|Estonia}}<ref>http://www.mil.ee/?id=888</ref>
*{{flag|France}}: Designated ''ABL'' (''A''nti ''B''lindé ''L''éger) by the [[French Army]].<ref>Replaced the [[APILAS]] [http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layout=1&eotf=1&u=http%3A%2F%2Fwww.defense.gouv.fr%2Fterre%2Fdecouverte%2Fmateriels%2Farmement_individuel_et_collectif%2Fat_4&sl=fr&tl=en Official French Ministry of Defense website]</ref> 
*{{flag|Georgia}}<ref name="jones2009"/>
*{{flag|Ireland}}: Called the ''SRAAW'' (''S''hort ''R''ange ''A''nti ''A''rmour ''W''eapon) by the Irish Defence Forces.<ref>The World Defence Almanac 2000-01 page 139 ISSN 0722-3226</ref>
*{{flag|Kazakhstan}}<ref name="jones2009"/>
*{{flag|Latvia}}<ref>[http://www.mod.gov.lv/upload/nbsfakti.anglu.gala.pdf National Armed Forces: Latvia]</ref>
*{{flag|Lebanon}}: Roughly 1000 pieces purchased.<ref name='dnnov1307at4smawd'>{{cite article| last = Kahwaji| first = Riad| title = Lebanon: Foreign Arms Vital to Hizbollah Fight| newspaper = Defense News|year = 2008| date = November 13, 2007| url =http://i43.tinypic.com/52i6u1.jpg}}</ref>
*{{flag|Netherlands}}<ref>The World Defence Almanac 2005 page 105 ISSN 0722-3226</ref>
*{{flag|Poland}}<ref>{{cite web |url=http://www.wp.mil.pl/en/galeria/1446 |title=Polish Army Photogallery (26) |publisher=Polish Ministry of Defence |accessdate=2010-04-26}}</ref><!--NOTE: See picture 26 in gallery.-->
*{{flag|Sweden}}<ref name="jones2009"/>
*{{flag|Taiwan}}<ref name="jones2009"/>
*{{flag|Ukraine}}<ref name="jones2009"/>
*{{flag|United Kingdom}}: Small quantities of AT4 and HP projectiles purchased.<ref name="kemp2006"/>
*{{flag|United States}}: Designated ''M136 AT4'' in [[United States Marine Corps|USMC]] and [[United States Army]] service, beginning in early 1987.<ref>[http://www.army.mil/cmh/books/DAHSUM/1987/ch05.htm Department of the Army Historical Summary, FY 1987], pg. 43.</ref> Over 300,000 built under license by ATK.<ref name="kemp2006"/>
*{{flag|Uzbekistan}}<ref name="jones2009"/>
*{{flag|Venezuela}}: The AT4 has been in the Venezuelan arsenal since the 1980s.<ref name="jones2009"/><ref name="janesvenezuela">http://www.janes.com/news/security/jiwk/jiwk090720_1_n.shtml</ref> In 2009 it was reported that AT4 weapons sold to Venezuela had been captured from [[FARC]] insurgents in Colombia, leading Colombia to accuse Venezuela of selling the weapons to the insurgents, and heightening tensions between the two countries.<ref name="janesvenezuela"/><ref>http://www.globalpost.com/dispatch/venezuela/090728/colombia-venezuela-tensions-rise</ref>

==See also==
* [[Urban Assault Weapon]]

==References and Notes==
{{Reflist}}

==External links==
{{Commons|AT-4}}
*[http://www.saabgroup.com/en/ProductsServices/products_az.htm?url=http%3A//products.saabgroup.com/PDBWebNew/Generic.aspx%3FEntrance%3DProduct%26ProductId%3D659 AT4 - Saab Bofors Dynamics]
*[http://world.guns.ru/grenade/gl11-e.htm AT4 Information Page - Modern Firearms]
*[http://translate.google.com/translate?hl=en&sl=sv&tl=en&u=http%3A%2F%2Fwww.soldf.com%2Fpskott.html Swedish article on AT4 translated to English]
*[http://www.globalsecurity.org/military/systems/munitions/at4.htm M136 AT4  - Global Security]
*[http://www.armyrecognition.com/forum/viewtopic.php?t=476 AT4 article with early photos and press releases and ads]
*[https://rdl.train.army.mil/soldierPortal/atia/adlsc/view/public/9681-1/fm/3-23.25/toc.htm#toc U.S. Army field manual 3-23.25]
*[http://translate.google.com.br/translate?u=http%3A%2F%2Fg1.globo.com%2FNoticias%2FRio%2F0%2C%2CMUL1529245-5606%2C00.html&sl=pt&tl=en&hl=&ie=UTF-8 Brazilian newspaper recorded a AT-4 at Rocinha slum (translated to English)]

{{ModernUSInfWeaponsNav}}
{{ModernUKInfWeaponsNav}}
{{Current French infantry weapons}}{{USAF Weapons}}

[[Category:Modern anti-tank rockets of the United States]]
[[Category:Weapons of Sweden]]
[[Category:United States Marine Corps equipment]]
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