AT4 CS, AT4-CS, AT-4CS
|Place of origin||Sweden|
|Used by||See Users|
|Manufacturer||Saab Bofors Dynamics|
|Unit cost||U.S. $1,480.64|
|Weight||6.7 kg (14.8 lb)|
|Length||102 cm (40 in)|
|Muzzle velocity||290 m/s (950 ft/s)|
|Effective firing range||300 m (point target)|
|Maximum firing range||500 m (area target)
2100 m (maximum)
|Sights||Iron sights, optional night vision unit|
|Filling weight||440 g HEAT (High Explosive Anti-Tank round)|
|Prototype AT4 Sweden tested 1981/82|
|Early AT4 with Swedish Soldier|
|Early AT4 launcher and projectile|
The AT4 (also variously AT-4, AT4 CS, AT4-CS, or AT-4CS) 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 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. It is intended to give infantry units a means to destroy or disable armored vehicles and fortifications, although it is not generally sufficient to defeat a modern main battle tank (MBT). The launcher and projectile are manufactured prepacked and issued as a single unit of ammunition with the launcher discarded after a single use.
The AT4 is a development of the 74-mm Pansarskott m/68  (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 anti-armor weapon that would not be able to defeat the heavy armor 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 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.
Even before the AT4 had been adopted by Sweden, it was entered into a 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 U.S. 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 to Congress in November 1983 that the FFV AT4 came the closest to meeting all the major requirements established to replace the M72 LAW, with the Armbrust coming in second.
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. 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 U.S. military forces in the last several years have been facing regularly, the U.S. 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.
The AT4 may be considered a disposable, low-cost alternative to a 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 inertia 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, the disposable AT4 design greatly reduces manufacturing costs by using a reinforced smoothbore fiberglass outer tube. In a recoilless weapon, the barrel does not need to contend with the extreme pressures found in traditional guns and can thus be made very lightweight. This fact, combined with the almost complete lack of recoil, means that relatively large projectiles (comparable to those found in mortars and artillery systems) can be utilized, 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.
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. It should be noted that the AT4-CS version also reduced its muzzle velocity from the original 290 m/s to 220 m/s as part of its effort to be user safe in a confined space, making the AT4-CS version less effective.
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, 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 sights and were originally developed for the cancelled Viper, and are similar in concept and use to those on assault rifles. He then removes the first of two 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 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 cannot be reloaded like the Carl Gustav.
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 9mm or 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 the 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).
- Length: 101.6 cm (40 in.)
- Weight: 6.7 kg (14.77 pounds)
- Bore diameter: 84 mm
- Maximum effective range: 300 metres (328 yards), although it has been used in excess of 500 meters (547 yards) for area fire.
- Penetration: 400 mm (15.7 inches) of rolled homogeneous armour (RHA) (also see below)
- Time of flight (to 250 metres, or 273 yards): less than 1 second
- Muzzle velocity: 285 metres (950 ft) per second
- Operating temperature: -40 to +60°C (-40 to +140°F)
- Ammunition: Fin-stabilized projectile with HEAT warhead
There are several different projectiles for the AT4. Note that because the AT4 is a one-shot weapon, projectiles are preloaded into the launcher tubes.
- HEDP 502 (High Explosive Dual Purpose)
- For use against bunkers, 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 for the HEDP projectile to either penetrate light walls or windows and then explode, or be "skipped" off the ground for an airburst. For use against light armor, there is a smaller cone HEAT warhead with 150 mm (5.9 inches) of penetration against RHA.
- HP (High Penetration)
- Extra high penetration ability (up to 500 mm (19.7 inches) to 600 mm (23.6 inches) 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.
- HEAT (High Explosive Anti-Tank)
- The HEAT projectile can penetrate up to 420 mm (16.5 inches) of RHA with beyond-armour effect.
- AT8 (Bunker-Busting)
- A version of the AT4 where the standard HEAT projectile is replaced with the bunker-busting warhead developed for the SMAW. No orders were ever placed.
- In the early 1990s, there were tests of a tandem charge 120-mm version (Bofors AT 12-T) that would be able to penetrate the front armor of any modern main battle tank. However, the project was canceled due to the dissolution of the Soviet Union and cuts in Western defense budgets.
- Argentina: Argentine Marines.
- Denmark: Designated PVV M/95 (Panserværnsvåben Model 1995).:93
- France: Designated ABL (Anti Blindé Léger) by the French Army.
- Indonesia
- Iraq: American forces supplied the Iraqi military with AT4 weapons.
- Ireland: Called the SRAAW (Short Range Anti Armour Weapon) by the Irish Defence Forces.:139
- Lebanon: Roughly 1,000 pieces purchased.
- Lithuania: Lithuanian Armed Forces.
- Netherlands (Replaced by Pzf-3)
- Sweden: Designated Pansarskott m86.
- United Kingdom: Small quantities of AT4 and HP projectiles purchased.
- United States: Designated M136 AT4 in USMC and United States Army service, beginning in early 1987. The AT4 was used in the U.S. invasion of Panama, the War in Afghanistan, the Persian Gulf War, and the Iraq War. Over 300,000 have been built locally, under license by ATK.
- Venezuela: The AT4 has been in the Venezuelan arsenal since the 1980s. In 2009, it was reported that AT4s sold to Venezuela had been captured from FARC insurgents in Colombia, leading Colombia to accuse Venezuela of selling the weapons to the insurgents, thus heightening tensions between the two countries.
- Panzerfaust 3
- ALAC (Arma Leve Anticarro)
- Urban Assault Weapon
- LAW 80
- M141 Bunker Defeat Munition
- RPG-76 Komar
References and notes
- Vapenexport (PDF), SE: Svenskafreds.
- M136 AT4, FAS.
- Kemp, Ian (April–May 2006), "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, ISSN 0252-9793.
- McManners, Hugh (2003). Ultimate Special Forces. DK Publishing. ISBN 0-7894-9973-8.
- Owen, William F. (2007). "Light Anti-Armour Weapons: Anti-Everything?" (PDF). Asian Military Review. Retrieved 2010-05-12.
- 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 1980, p. 70.
- Military Channel, "Weaponology" program, "Grenades through 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)
- Pansarskott is a Swedish term that roughly translates to "Armour Shot."
- International Defense Review, May 1980, p. 71.
- 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.
- 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.
- the U.S. Army had so much grief in the early 1980s from various committee members of the U.S. 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
- John Antal "Packing a Punch: America's Man-Portable Antitank Weapons" page 90 Military Technology 3/2010 ISSN 0722-3226
- 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.
- 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.
- the complete disposable launcher and HEDP projectile is referred to by the manufacture in brochures as the LMAW - i.e., light multipurpose-assault weapon -- see external links for link on early photos and press releases for further information on brochure
- 2008 SAAB video on AT4 versions including new multipurpose warhead for urban combat
- History Channel, Lock N' Load With R. Lee Ermey, Rockets episode, aired October 23, 2009.
- 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 SMAW-D offered by Talley was chosen for the U.S. Army program that the AT4 entered. See external images at the SMAW-D link for an arms brochure on the FFV AT8
- La Infantería de Marina adquirió armamento antitanque descartable
- Jones, Richard D (January 27, 2009), Infantry Weapons 2009/2010 (35 ed.), Jane's Information, ISBN 978-0-7106-2869-5.
- The World Defence Almanac, 2000–01, ISSN 0722-3226 .
- Mil, EE.
- Replaced the APILAS: AT 4 CS - L'arme anti blindé lourd AT 4 CS - The Armoured Heavy anti gun, France: Ministry of Defense, retrieved 29 June 2013.
- Sverigesradio, SE.
- The World Defence Almanac, 2010, p. 172, ISSN 0722-3226.
- Kahwaji, Riad (November 13, 2007). "Lebanon: Foreign Arms Vital to Hizbollah Fight" (JPEG). Defense News.
- The World Defence Almanac, 2005, p. 105, ISSN 0722-3226.
- Polish Army Photogallery (26). Polish Ministry of Defence. Retrieved 2010-04-26.
- "Modernizing and Equiping the Army". Department of the Army Historical Summary, FY. United States Army Center of Military History. 1995. p. 43. CMH Pub 101-19.
|Wikimedia Commons has media related to AT-4.|
- AT4 - Saab Bofors Dynamics video of various AT-4 versions
- AT4 Information Page - Modern Firearms
- Swedish article on AT4 translated to English
- M136 AT4 - Global Security
- AT4 article with early photos and press releases and ads
- U.S. Army field manual 3-23.25
- Brazilian newspaper recorded a AT-4 at Rocinha slum (translated to English)
- Official site for the AT4, covering the different versions of AT-4