What does AT4 stand for? 

AT4

The AT4 is a Swedish 84 mm (3.31 in) unguided, man-portable, disposable, shoulder-fired recoilless anti-tank weapon manufactured by Saab Bofors Dynamics (formerly: FFV Ordance, later, Bofors Anti-Armour Systems). The AT4 is not considered a rocket launcher as the explosive warhead is not propelled by a rocket motor; similarly, it is not exactly a recoilless rifle, but rather a recoilless gun, as the launcher is smoothbore and not rifled. Saab has had considerable sales success with the AT4, making it one of the most common light anti-tank weapons in the world. The M136 AT4 is a variant used by the United States Army. The name AT4 is a word play on the 84 mm caliber of the weapon, (84) 'eighty four' being a homophone of 'A-T-4'. The name also doubles as an alpha-phonetic word play on the weapon's role, due to "AT" being a common military abbreviation for "anti-tank". The name was created for export purposes as the nickname "eighty-four" was already a common English nickname for the Carl Gustaf 8.4 cm recoilless rifle after its caliber.The AT4 is intended to give infantry units a means to destroy or disable armoured fighting vehicles and fortifications, although it is generally ineffective against more modern main battle tanks (MBTs), especially those with reactive armour, unless weaker sections of armour are exploited. The launcher and projectile are manufactured prepacked and issued as one unit of ammunition, with the launcher discarded after one use.

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