AT4

The AT4 is a single use rocket launcher designed to destroy armored vehicles and fortifications. Designed by Saab Bofors Dynamics, the AT4 was adopted by the United States Army after some reworking as the M136 LAW, replacing the older Vietnam-era M72 LAW. Adopted by 21 countries, the AT4 is one of the most successful light missile launchers made. The United states military designed the AT4 to be a recoilless weapon. The AT4-CS (confined spaces) was the first rocket designed to be fired from within the confines of a building. The blowback blast is negated by a saltwater countermeasure in the back of the tube making it safe to fire with friendlies around.

Call of Duty 4: Modern Warfare
The AT4 is seen on ally Marines, but is unusable by the player (unless you use the "give all" cheat). It's only used by allies twice; both times in "Shock and Awe". The first one is after some allies are let out near the statue. One of them has an AT4 and will fire it after hiding behind a wall. He's very close to the player, so they should see him get into position and fire before the player takes off. The last time is when the player gets to the stranded allies in the under-construction building; one of them will fire it into the crowd of troops right before the player gets to the top. It is occasionally seen carried by Ultranationalists, but they never use it.

The AT4 can be used on the levels "Shock and Awe" and "Game Over" by entering "give at4" in the console (this will only work on the PC version). The gun, which is normally dropped by NPC's after firing, has no reloading animation. So when it is fired by using the cheat, it is just suddenly reloaded and ready to fire again.

Call of Duty: Modern Warfare 2
The AT4 debuts as a usable weapon in Call of Duty: Modern Warfare 2. This version is called the AT4-HS (Heat-Seeking) as it is capable of locking on to aircraft. To lock-on, the weapon must be ADS aimed at the aircraft until a clear, loud tone is heard then fired. Even when locked on, the AT4 occasionally misses. These misses may be caused by the user firing before the tone is perfectly clear and loud.

In-game it can also be dumb-fired without locking on, operating like a more accurate but weaker RPG-7. This makes it somewhat effective against infantry and ground equipment, if a bit underpowered. However, only a single rocket is available, (you can re-load the AT-4 if you are using the Scavenger perk) so once used it is highly recommended to replace it with another backup weapon.

In terms of strategy, the AT4 does not replace the Call of Duty 4: Modern Warfare ' s RPG in terms of multiplayer combat. The AT4 takes crucial moments to switch to, load, and ready. Also, the ability to melee is slowed down due to the bulky nature of the device. Players using the Scavenger perk can pick up extra rockets from recently killed players from both teams, the transitioning between swapping out the launcher is slow but ensures that the AT4 has a second rocket available during the match.

The AT4 is weaker than the Stinger or Javelin for taking out aircraft and inferior to the Thumper for clearing out buildings. However, it can fill either role since it doesn't require a lock-on but there is one available. This inferiority is further mitigated by the fact that the weapon is available in the earliest stages of the game and that, unlike the Thumper, while the AT4 has no arc to worry about. Finally, it can be dumb fired against aircraft, exposing the user for a shorter period of time than waiting for lock and avoiding the aircraft's flares. This is only recommended against slow moving aircraft.

Like the RPG the AT4 must be fired from iron sights. Pressing the fire button from the hip will raise the iron sights first before firing. The AT4 sights are extremely obtrusive with a very large frame blocking the area surrounding the target.

Like the Javelin the AT4 has slightly unusual loading behavior when used with Scavenger. An AT4 user may carry two missiles, one in reserve and one in the launcher itself. However, additional missiles can only be picked up if the launcher is actively equipped and the reserve slot is open.

One major advantage the AT4 has over the RPG is that the AT4's missile flight is almost perfectly straight, while the RPG can go wildly off course. Even at long ranges, the AT4 is highly accurate, similar to a decently accurate assault rifle, while with the RPG you have to be very lucky to hit your target.

Trivia

 * In Call of Duty 4 the AT4 was originally supposed to be given to you as part of a perk. While unknown how the perk would work, it was possibly designed as a USMC or SAS replacement for the RPG-7. The perk's icon still remains in the files, along with a kill picture.
 * The AT4 can be used on the map "Shock and Awe" and "Game Over" by entering "give at4" in the console. This only works on PC version.
 * The player can see the AT4 in F.N.G. in the armory.
 * In Modern Warfare 2's multiplayer, if you fire a rocket without locking on to an enemy air support it cannot be diverted by flares. As the AT4 and the RPG are the only free fire launchers, this only works with them.
 * AT4 is a play on words. The round that is fired out of this weapon is an 84mm round. 84 sounds like AT4.
 * In reality, the AT4 is not capable of locking onto any kind of vehicle, as the rocket is a "dumb" unguided munition.
 * The AT4 in reality is a one-shot weapon. Once the missile is used up, the empty tube is discarded by the user and a new tube is taken out.
 * In reality if you were to shoot an AT4 in a confined space you would die unless you were using the AT4-CS.
 * The AT4 only costs $1,480, but the Stinger costs $38,000 and the Javelin costs $125,000, making it cheaper than other launchers but held back by single use only.
 * In Modern Warfare 2, the AT4 is the first launcher to be unlocked.
 * When viewed in 3rd person or when dropped, the AT-4 is quite detailed. There are many images showing operation of the weapon and a picture of the backblast effect that makes the AT-4 dangerous to fire in enclosed spaces. There are also instructions on how to properly fire the weapon. The directions state:"Aim-Set Range if known or if estimated to be greater than 250 meters. Push Safety and hold down fire by pushing trigger." The weapon also has barcodes.
 * A special title is unlocked for getting 250 and 500 multi-kills with this weapon after you've prestiged.