AT4
The AT4 is a lightweight, man-portable, single-use 84 mm unguided recoilless anti-tank weapon system developed in Sweden and manufactured by Saab Bofors Dynamics.[1] Designed for infantry use, it fires a fin-stabilized high-explosive anti-tank (HEAT) warhead from a disposable fiberglass-reinforced tube, enabling effective engagement of armored vehicles, bunkers, and low-flying aircraft at ranges up to 300 meters.[2] The system emphasizes simplicity, with a striker-fired mechanism and integrated sights for rapid aim-and-fire operation by any trained soldier, while the confined-space variant incorporates a saltwater countermass for safe firing in enclosed environments.[3] Originating from the 74 mm Pansarskott m/68 system used by the Swedish Army in the 1960s, the AT4 was developed by Försvarets Fabriksverk (FFV) in the late 1970s as a more capable successor, with prototypes tested by 1982 and full production beginning in 1985.[2] It gained international prominence when adopted by the United States Army as the M136 in 1987, leading to over 600,000 units delivered to U.S. forces alone and more than 1 million produced globally.[2] Combat-proven in conflicts including the Gulf War, Iraq, and Ukraine, the AT4 has been supplied to over 20 countries, such as the UK, France, Iraq, and Ukraine, underscoring its role as one of the most widely used light anti-armor systems worldwide.[3][1] Key specifications include a total weight of approximately 6.7 kg for the standard model (7.5 kg for confined-space variants), an overall length of 1,020 mm, and a muzzle velocity of 290 m/s, with armor penetration ranging from 400 mm to over 600 mm of rolled homogeneous armor (RHA) depending on the warhead.[2][3][4] The weapon features plastic range-adjustable sights and compatibility with night vision optics, while its minimum arming distance of 10 meters enhances safety during urban operations.[2] The AT4 family includes several variants optimized for specific threats: the AT4-CS (confined space) for enclosed environments, AT4-CS ER (extended range) reaching 600 meters, AT4-CS HP (high penetration) for heavily armored targets, and specialized rounds like the AT4 AST (anti-structure) for bunkers or the AT4 HE (high explosive) for personnel and light vehicles.[1][2] These adaptations maintain the core disposable design, ensuring low logistics burden and high reliability in diverse operational scenarios.[3]History
Etymology
The name "AT4" derives from the abbreviation for "anti-tank" combined with the numeral 4, while also functioning as a phonetic play on the weapon's 84 mm caliber, with "eighty-four" serving as a homophone for "A-T-4" in English pronunciation.[5][6] This dual interpretation highlights the system's primary anti-armor purpose without implying advanced features like guidance. In Swedish defense nomenclature, such caliber-referenced identifiers maintain continuity with prior systems, exemplified by the Pansarskott m/68—a 74 mm disposable recoilless rifle adopted in 1968 and later succeeded by the AT4 in 1986 as Pansarskott m/86.[7][8] The "Pansarskott" prefix, meaning "armor shot," underscores this tradition of straightforward, function-based labeling for light anti-tank weapons. By evoking "anti-tank" through its acronym and sound, the AT4 designation emphasizes its design as a man-portable, single-use system optimized for infantry engagement of armored targets via unguided projection, prioritizing ease of deployment over reusability or precision targeting.[9]Development
The AT4 originated as a successor to the Swedish Pansarskott m/68, known as the Miniman, a disposable 74 mm recoilless anti-tank weapon introduced in the late 1960s that suffered from limited effective range of around 100 meters and insufficient armor penetration against modern tanks.[8] Developed to address these shortcomings, the AT4 increased the caliber to 84 mm while retaining the single-use, man-portable design for infantry use.[2] Key development work commenced in the late 1970s under FFV Aerotech, a division of the Swedish defense firm Försvarets Fabriksverk (now part of Saab Bofors Dynamics), aiming to enhance warhead effectiveness and minimize back blast hazards through improved propulsion and venting systems.[2] Prototypes underwent initial testing in Sweden during 1981 and 1982, demonstrating superior performance in penetration and reliability compared to the Miniman.[10] In 1983, the U.S. Army evaluated the AT4 alongside five other anti-tank systems—including the British LAW 80, German Armbrust, French APILAS, Norwegian M72E4, and Israeli RPG-7—during trials at Aberdeen Proving Ground from April to July, where it excelled in ease of use, accuracy, and armor defeat capabilities.[10] This led to its selection to replace the aging M72 LAW, with formal U.S. adoption as the M136 Light Anti-Armor Weapon in 1987 following minor modifications to sights, slings, and bumpers for American specifications.[2] By 2025, global production had surpassed 1 million units, primarily driven by U.S. and NATO demand.[1] In response to post-2020 demand surges from conflicts like the Russia-Ukraine war, Saab secured an Indefinite Delivery, Indefinite Quantity contract in August 2024 valued at up to US$494 million with the U.S. Army to ramp up production of AT4 variants for NATO allies.[11]Design and Operation
Operation
The operation of the AT4 follows a simple, step-by-step firing sequence optimized for quick use by infantry personnel. The operator begins by cradling the weapon in the left arm and removing the transport safety pin, which disarms the initial safety lock. Next, the flip-up iron sights are extended and adjusted for range, typically calibrated to a point target at 300 meters using the front post sight and rear peep aperture. The weapon is then shouldered with the rubberized stop extended against the right shoulder, aimed at the target, and the cocking lever is pulled rearward to arm the mechanism while holding down the forward safety button; finally, the trigger is pressed to ignite the propellant charge, propelling the projectile forward while the back blast danger zone—extending approximately 40 meters rearward in a 90-degree fan—must remain clear of personnel, equipment, or obstructions to prevent injury from heat, blast, and debris..pdf)[12] The AT4's recoilless design relies on a countermass system to neutralize recoil forces, employing plastic blowout plugs at the rear of the launch tube in the standard variant to vent gases rearward and maintain balance during firing. This allows the 1,020-millimeter-long, 6.7-kilogram weapon to be handled portably without significant kickback to the user. In the AT4-CS confined-space variant, the plastic plugs are replaced by a saltwater solution countermass, which absorbs much of the back blast energy and minimizes toxic gas production, enabling safer discharge in urban or enclosed areas with reduced risk to nearby personnel.[2][13] Safety features emphasize prevention of accidental discharge through a multi-layered system, including the transport safety pin that blocks the firing mechanism until removed, the forward safety button that must be depressed to allow trigger activation, and the cocking lever that arms the firing rod only when intentionally positioned. As a single-use disposable weapon, the fiberglass-reinforced plastic tube is non-reloadable and is discarded entirely after firing to preclude reuse or mishandling..pdf)[14] Due to the AT4's intuitive design and minimal mechanical complexity, training requirements are limited to basic familiarization, focusing on safe handling, sight alignment, and trigger control, typically completed in a single session for qualified personnel. However, instruction places strong emphasis on back blast hazards, requiring operators to verify clear zones and adopt proper stances—such as kneeling or prone positions—to mitigate risks, particularly in confined urban environments where obstacles can amplify blast effects..pdf)Technical Specifications
The AT4 is a lightweight, disposable, single-use anti-armor weapon system featuring a smoothbore recoilless launcher tube preloaded with an 84 mm fin-stabilized high-explosive anti-tank (HEAT) cartridge.[15] Its design emphasizes portability and simplicity, with the entire unit constructed from a fiberglass-reinforced epoxy tube for durability and reduced weight, allowing one soldier to carry and employ it without specialized training beyond basic familiarization.[16] The fixed round incorporates a rocket motor using a double-base propellant formulation, providing initial propulsion via a confined backblast while the warhead achieves stable flight through rear-fins.[17] Key performance parameters include an effective range of 300 meters against point targets such as armored vehicles and up to 500 meters for area targets, with a muzzle velocity of 290 m/s for the standard HEAT projectile.[15] The HEAT warhead delivers penetration of approximately 400 mm of rolled homogeneous armor (RHA), sufficient for defeating light to medium armored threats while producing spall and overpressure effects beyond the armor.[15] The system operates reliably in extreme conditions, from -40°C to +60°C, and has a certified shelf life of 20 years under proper storage.[16][18]| Specification | Standard AT4 | AT4-CS Variant |
|---|---|---|
| Length | 1,020 mm | 914 mm |
| Mass | 6.7 kg | 8 kg |
| Caliber | 84 mm smoothbore | 84 mm smoothbore |
| Effective Range | 300 m (point), 500 m (area) | 300 m (point), 500 m (area) |
| Muzzle Velocity | 290 m/s | 220 m/s |