AT4

The AT4 is a shoulder fired, disposable anti-tank rocket launcher featured in Call of Duty 4: Modern Warfare and Call of Duty: Modern Warfare 2.

Call of Duty 4: Modern Warfare
The AT4 is seen on allies, but is only usable by cheats. 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.

The AT4 can be used on the levels "Shock and Awe" and "Game Over" by cheating (this will only work on the PC version). The weapon, 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.

In multiplayer, the AT4 was originally supposed to be given to the player as a first tier perk. The perk's icon still remains in the game files, along with a kill picture.

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 Launcher) as it is capable of locking on to aircraft. To lock-on, the weapon must be ADS aimed at a aircraft until a clear, loud tone is heard and then fired. Even when locked on, the AT4 occasionally misses. 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.

Tactics
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.

The AT4 is weaker than the Stinger or Javelin for taking out aircraft and inferior to the Thumper for clearing out buildings, although it does have a larger radius and more damage than the Thumper and therefore is a good compromise. Like other launchers, the AT4 rocket gives off a long path of smoke, making the user vulnerable to detection. The iron-sights are very bulky and create a very large blind-spot. The AT4 has only one rocket by default, though more can be picked up using Scavenger.

Despite its apparent disadvantages, the AT4 can prove very useful in any game mode. It can fill many roles because it does not require a lock-on, but it can lock on when necessary. The weapon is available in the earliest stages of the game and, unlike the Thumper, the AT4 has no arc to its shots. The explosion from the rocket is powerful and has a large blast radius. Firing the AT4 into rooms or buildings can efficiently kill or heavily damage any enemies inside. It can be dumb fired against aircraft, exposing the user for a shorter period of time than waiting for a lock while avoiding the aircraft's flares. This strategy can be somewhat difficult to do unless the aircraft is close to the player or not moving. Despite being weaker than other launchers, it is still able to destroy Sentry Guns in one shot, but it has to be a direct hit.

One major advantage the AT4 has over the RPG is that the AT4 rocket's flight path is almost perfectly straight, while the RPG can go wildly off course. That allows AT4 users to fire accurately at long ranges. The AT4 rocket also flies much faster than the rocket of the RPG, thus making it more effective in taking out targets that are moving.

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

Trivia

 * In Modern Warfare 2, the rocket's velocity is 6.31 m/s, or 21 feet per second.
 * Strangley the AT4 can take out a AC-130 in a single hit but helicopters and harriers take 2 or 3 but in realit a AC-130 could take more than 1 while a helicopter (depending on were its hit) whould lose control in 1 hit same going for RPG-7.

Video
thumb|300px|left|Video showing the accuracy of the AT4; it is accurate enough to get a headshot at medium-long range