In the mid 1970's (1976), the Swedish Armed Forces were looking for a replacement for the Pansarskott m/68 ("Miniman") anti-tank launcher. In the period 1976-1980 the new launcher was developed by Förenade Fabriksverken (FFV) and entered into trials with the Swedish Army in spring of 1981. The new launcher in commercial parlance would come to be called the AT4 (sounds like "84", the caliber in mm).
The AT4 was specifically designed not to penetrate the frontal armor of main battle tanks as this was considered counter-productive. With the Swedish Armed Forces being the initially most likely operator, it is likely (though I have no supporting data) that this was done to encourage ambush-type engagements rather than head-to-head engagements that was part of the Swedish military's doctrine. The AT4 can however defeat the majority of infantry fighting vehicles and armored personnel carriers of the Soviet Union/Russia from all aspects.
Prior to it's adoption by the Swedish Armed Forces, the AT4 was also entered into trials (1982) with the U.S. Army. The AT4 won the trial but was lightly modified with front and rear bumpers on the launcher to prevent damages to the launcher during transportation. The Swedish military followed suit when they adopted the AT4 in 1986 as the Pansarskott m/86 and added the bumpers, but also included a forward grip for increased stability.
The AT4 is a single-use disposable launcher.
To enhance the weapon's viability and use in urban environments, a confined spaces variant was developed which used a small amount of salt-water packed behind the rocket which limited the backblast of the weapon. While still generally discouraged, the CS variant can be fired from smaller rooms like apartments of similar. The CS variant quickly replaced the non-CS variant in widespread international use.
The AT4 comes in a variety of flavors for all your destructive needs:
The AT4 features integrated iron sights which, when stowed, are contained in two small plastic containers on the front-end of the launcher tube. When opened, the iron sight will deploy automatically by spring pressure. These iron sights are pretty basic, a round hole and regular front post. The rear iron sight has the ability to switch between two sizes of peep-holes (2mm or 7mm).
The Swedish Pansarskott m/86 has a feature that is not present on the U.S. military M136; two additional posts that can be used for rudimentary rangefinding of a 7 meter target (side of a BMP vehicle).
Some AT4 systems have been equipped, funnily enough, with red-dot sights, despite being a disposable weapon launcher intended to be discarded after use.
The AT4 features two safeties; a travel safety and a safety lever. The travel safety is located at the back-end of the weapon and is a simple pin safety that is turned 90 degrees and then removed when disabling said safety. The safety lever is located (when in a firing position) just next to the shooter's face and is pushed forward and rotated to the right to disengage the safety.
Once both safeties have been disengaged, the weapon is fired by pressing a small red button on the right hand side of the weapon, just in front of the safety lever.
The projectile has a minimum arming distance of 30 meters.
Being a recoilless weapon, the weapon does have a significant backblast that, while reduced, is present on the CS variant as well. The safety zone is approximately 45 degrees and 15 meters behind the weapon.
The AT4 has the remarkable ability of being able to be used as a anti-vehicle mine where the weapon is mounted on a tree and triggered remotely by wire from cover.
Soldaten i Fält (2001)
Soldatreglemente för vapenmateriel Pansarskott 86 (2000)