AT4

The AT4 is an one-shot rocket launcher designed to destroy armoured 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.

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).

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 was revealed in a multiplayer trailer to be capable of firing surface-to-air missiles (the target being an AC-130H Spectre). This is strange, as the real-life AT4 is an unguided anti-tank weapon, and its current function is that of the FIM-92 Stinger in Call of Duty 4: Modern Warfare; in fact it uses the same sound effects when locking on, which indicates it as a mistake on Infinity Ward's behalf. In-game it can operate much like a more accurate, but weaker RPG-7; but is more of a multi-functional weapon, capable of destroying enemy equipment such as defense turrets, helicopters, and infantry. However, only a single rocket is available, so once used it is highly recommended to replace it with another backup weapon.

Even though this weiner is lock on launcher, even when the launcher is locked onto a target it doesn't always hit the designated target.

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.

Trivia

 * The AT4 was originally supposed 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.