The SAM Turret is an unmanned weapon which automatically locks onto any aircraft killstreaks and fires missiles to destroy them. The turret is capable of taking out nearly any airborne killstreak (exceptions include the Stealth Bomber and Blackbird). However, the SAM Turret has a limited amount of missiles and is completely defenseless against ground targets. The SAM Turret will fire at aircraft from any location it's placed, even if it means firing at a wall.
The SAM turret can shoot down all enemy airborne killstreaks, including Valkyrie Rockets, but not the Blackbird. Airstrike-class killstreaks such as Napalm Strike and Rolling Thunder can't be shot down. Like the Sentry Gun, this killstreak must be called in by airdrop before placing it. The SAM turret only fires a limited number of missiles, and then self-destructs. The player can only place two SAM turrets at once. Placing a third turret will destroy the first one. Like the Sentry Gun, the SAM turret can be destroyed by the enemy team. The SAM turret picks its targets based on how long they've been active, not by how dangerous they are. For instance, a SAM Turret would first destroy a Spy Plane that's been active for 20 seconds then attack a Gunship that has been up for 10 seconds. The rocket from it travels fast, even faster than the Valkyrie Rocket. One knife slash will destroy it. SAM turrets last 1 minute and 30 seconds - three times the time of Counter Spy Planes. The SAM Turret will wait until the Spy Plane scans the map one time before firing a missile at it.
The SAM Turret returns in Call of Duty: Modern Warfare 3 as an 8-point Support Strike package pointstreak. It takes a few seconds to automatically lock on to enemy air support and fires a salvo of four surface-to-air missiles at it. The missiles can trigger flares and be diverted. The missiles launched by the turret are significantly weaker than those fired by the turret in Black Ops, requiring all four to hit a simple UAV or counter UAV to destroy it; other pointstreaks, such as helicopters, will require over four missile hits to be destroyed. This is somewhat balanced by the turret's ability to fire a seemingly unlimited amount of missile salvos at air support.
Unlike in Black Ops, it does not need to be airdropped in and can be deployed as soon as the player earns it. Destroying an enemy SAM Turret also adds a point to a player's pointstreak.
Placing it in an open area is recommended, as many buildings and/or structures have a tendency to block the SAM Turret's missiles, though this could lead to it being destroyed by enemies more quickly.
The SAM Turret as it appears in MW3.
The SAM Turret in Modern Warfare 3. Note the faction icon.
The SAM Turret firing on an enemy Hind.
A SAM turret in MW3
A destroyed SAM turret.
An unused killstreak icon for the SAM turret in MW3.
The turret can kill its owner if its owner is standing near the rocket explosion. The rocket will pass through friendly players without detonating, but if it impacts a wall or its target and its owner is too close, it will kill them.