Sentry Gun



"Sentry Gun on the way!"

- Multiplayer announcer when a teammate calls in a Sentry gun.

The Sentry Gun is an unmanned weapon capable of autonomously acquiring and defeating enemy targets by using thermal detection. It, as well as the UAV and Predator, is indicative of the increasing role of unmanned technology on the battlefield.

Campaign
M5 Sentry Guns are seen inCall of Duty: Modern Warfare 2's campaign various times. They first appear in the level "Wolverines!". The Sentry in this level is positioned on top of Nate's Restaurant, where it provides autonomous cover for Sergeant Foley and his team during the recovery of codename "Raptor". Ramirez (the player character) can reposition the sentry gun if needed. An enemy sentry gun is seen in "Exodus", so this may be a clue that the Ultranationalists made an exact copy of the Sentry Gun, since the Sentry gun is likely to be a unique weapon, made only for US Military. Parts of a sentry gun can be found throughout Makarov's safehouse in the level "Loose Ends". Sentry guns can also be found during the level "Endgame" on one of the banks during the boat chase before you go through the cave.

Special Ops
Sentry guns are available for use in the levels Homeland Security, Wardriving and Wreckage. They are used in Homeland Security to defend from inside of the gas station and adjacent building. They are used in Wardriving to guard the locations of the computers as the files are downloaded. They are used in Wreckage to kill enemies and destroy the vehicles.

Multiplayer
The Sentry Gun is a multiplayer killstreak reward in Call of Duty: Modern Warfare 2. After achieving a killstreak of 5 (or 4 with the Hardline perk), a player may call in a helicopter that will airdrop a package (similar to the Care Package killstreak) containing the Sentry Gun. After acquiring the package, the player can place the gun in the location of his choice. It can detect enemies at a moderate distance, with its cone of fire centered on where its user positions it. The turret can be picked up and moved; the turret is disabled while held, and the player is unable to use weapons or other equipment. If not destroyed, the turret will expire after 90 seconds, appearing to short-circuit itself.

Any players with the Cold-Blooded perk will not be targeted by the turret (though they are still vulnerable to shots fired at other targets). The sentry gun can be disabled with a single melee hit or by gunfire. A flashbang or stun grenade disables the Sentry Gun for a few seconds, leaving it vulnerable to knife. It can also be avoided by moving around its flank, outside of its firing arc. A riot shield user can approach the sentry gun and knock it down with the shield bump, or let the gun destroy itself with ricochet hits. A certain number of destroyed sentry guns will remain on the map and will only vanish when more sentry guns are placed. These destroyed guns form a visual distraction, both because players will approach them cautiously as it's hard to tell if a gun is active or disabled and because they are so bulky, allowing players to hide behind them. They can, however, be fired and walked through.

In objective-based games such as Capture the Flag or Sabotage, the Sentry Gun can provide valuable support while protecting a flag or bombsite. Even on Hardcore, the gun can absorb a decent amount of gunfire before being destroyed. However, it can be destroyed by indirect fire through predator missiles or other aerial support weapons. Despite the nature of Hardcore giving players much less health, the Sentry Gun is not very effective on hardcore because most players are using cold-blooded, or can easily avoid the Sentry Gun, then either disable it, or just keep away from it.

Sentry Guns can be beneficial for snipers for numerous reasons. First, Snipers can only have one claymore (Without Scavenger or One Man Army) to cover them while they snipe. Sentry Guns can provide cover for the sniper rather than a claymore meaning the player does not have to sacrifice a Frag grenade, Throwing Knife, etc for a claymore. Also, unlike claymores where the enemy can come in quite close, sentry guns can keep enemies pinned down at a distance and thus, not allowing the enemy to get in close enough to shoot the player at an angle or throw a grenade at the player.

Sentry guns have 1000 health points and no damage multipliers. Melees destroy them instantly, explosives do 7x their base damage to them. (so if an AT4 does 160 base damage, it will do 1120 damage with a direct hit to a sentry gun) Bullet damage is the same.

Tactics

 * It is best that you place a sentry gun with its weak backside against a wall so that it can't be flanked.
 * Semtex grenades are very effective at neutralizing Sentry Guns. It only takes one well-aimed Semtex grenade to disable it.
 * Place your sentry guns to guard a high priority objective like a flag or bomb site, that way there are fewer players needed to defend such objectives.
 * If a player obtains one in an Emergency Airdrop, it is advised to grab the Sentry Gun first and quickly set it up to cover the other crates. This tactic can also be used to cover yourself or teammates calling any sort of package in or whilst using a player operated killstreak such as AC-130.
 * Long open corridors are some of the best spots to place your gun since no one can run from it or make a successful escape. Some such spots are the plane in Terminal or the ramp toward the Militia spawn in Quarry.
 * Having Cold-Blooded will allow you to approach the sentry without it shooting you. However, the sentry gun will still fire upon an ally behind you that does not have the Cold-Blooded perk, hurting you in the process.
 * Bring the Sentry Gun behind windows or on high places to allow it to engage targets without having its base directly exposed to gunfire.
 * When sniping, use the Sentry Gun to defend your backside and the entrances with claymores to make your campsite fairly safe.
 * The sentry gun will fire through smoke. Using a smoke grenade to "hide" the sentry can be effective, as opponents may not see the sentry before it is too late.
 * You can go in front of a Sentry Gun with a Riot Shield. This will give you a high amount of experience. This was a form of boosting in third person cage match before it was removed.
 * A sentry gun can be concealed by plants and other objects, most notably in Favela and Karachi.
 * The Sentry Gun can be destroyed by a single melee attack from either a Knife, or Riot Shield. However, a Throwing Knife will not disable it in one throw.
 * If you are killed while carrying a Sentry Gun, the Sentry Gun will drop on your current position and will most likely start firing at the person who killed you.
 * Place the sentry on higher ground as it shoots down better than it would shooting up at enemies.
 * On Skidrow, if your team has control of the stairs to the center hallway, you can deploy your sentry gun to kill enemies all the way to the other side of the hall, while concealing 75% of itself from return fire.
 * Sentry Guns can also be used as bait. Many players, especially on Hardcore, will be using Cold-Blooded and attempt to knife the gun from behind. This can be used to eliminate any players that attempt to do so by keeping an eye on your gun.
 * If, on Highrise you place a Sentry on the roof of the southern building, or, less effectively, the second floor of the northern building, the gun can achieve long-range cross-map kills, and the guns are very hard to destroy.
 * There is a tip shown when the game loads a multiplayer map that alleges that Sentry Guns can be temporarily disabled by throwing a flashbang or stun grenade at it.
 * Place a Claymore behind your sentry gun, facing in the opposite direction (back to back) so that knifers get killed if they try to slash the sentry.
 * Placing a sentry gun on top of a destroyed car gives it a much better kill zone, although the car must be destroyed prior to placement otherwise it will destroy the sentry gun when it explodes.
 * Sentry Guns can be used as improvised AA; a gun on an elevated position will fire on enemy killstreak awards.
 * To easily disable the sentry gun, equip a sniper and get within range of the sentry so that you can only see its leg. Using this tactic, the sentry gun can not attack you, while you shoot the sentry's leg. This can be riskful in a one on one match due to the fact that a player can kill you from behind. If done in a multiplayer round, your team mates can guard you while you destroy the sentry gun.

Pros and Cons between the Predator Missile and Sentry Gun
Both require 5 kills (4 with Hardline)
 * A Predator Missile is controlled by a laptop, leaving you on the ground and easily killed, whereas a Sentry Gun can be placed to kill an opponent. Nevertheless, both can leave you defenseless while using. However you will be more vulnerable while placing a Sentry since you will stand out very clearly for as long as you haven't placed the Sentry Gun, a Predator Missile will only leave you vulnerable when you are controlling it, which could be anywhere between 2-5 seconds.
 * If you die while placing a sentry turret, it gets placed where you died. When you die while controlling a Missile, you may continue controlling it.
 * A Sentry gun must be air dropped before use but a Predator missile can be used instantly.
 * Predator is a better way to get the immediate kill, but a well placed Sentry Gun can get far more kills than the missile.
 * Predator Missiles can destroy almost any killstreak, including a Chopper Gunner, or even with extreme luck an AC 130. A Sentry Gun can destroy some killstreaks like Attack Helicopters, but require some assistance.
 * A Sentry Gun can't detect a Cold-Blooded player. A Cold-Blooded player is still visible by the user controlling a Predator Missile, but the red box indicating a hostile is removed.
 * A Sentry Gun automatically disables itself after 90 seconds even if untouched, no matter how many players it has killed. A Predator Missile can be saved for later, but you have to press the killstreak button or switch weapon button just before you enter the Missile Camera.
 * A Predator Missile's kills add to your killstreak count. Only the first sentry gun called in will add to your killstreak.
 * You have only one chance to use the Predator Missile, if you fail, you just lost an opportunity to gain a couple more kills for a higher killstreak. The Sentry Gun can be placed anywhere valid, you set it up and it does its job, making it easier to leave alone and get many kills.
 * Due to the fact the Sentry Gun glows yellow when being placed, players setting up the Sentry Gun can be spotted quite easily and, if attacked or stabbed from behind, the Sentry Gun can be quickly disabled.
 * If the player has deployed a Sentry Gun, if the player is killed when the Sentry Gun glows red when re-locating it, the Sentry Gun will disappear.

Trivia

 * A sentry gun with no tripod can be found on the mission Loose Ends inside the weapons cache room, although it is not usable. It clips through the ammo box and the shelf partially.
 * The original sentry gun concept art used a XM312 machine gun instead of a M134 minigun.
 * An EMP can disable the Sentry Gun.
 * A Sentry Gun can acquire and destroy helicopters and Harriers. It can even acquire an AC130, but cannot destroy it.
 * The Sentry Gun has a Picatinny rail attached to it. However, no upgrades are actually available for the gun.
 * In the single player level Wolverines! you can actually move the Sentry Gun out of Nate's and bring it with you to your other targets, which can make the level much easier.
 * The Sentry Gun has a 180 degree angle within which it can engage targets.
 * Much like the Pave Low, only the first Sentry Gun to be called in adds to your killstreaks. Any other Sentry Guns called in the same game, by any team, will not add to killstreaks.
 * There is a limit of 32 total Sentry Guns on a map.
 * If a player is killed while holding a Sentry Gun, it will drop to the ground and deploy where they died and facing in the direction it was held. However, this only applies if the Sentry Gun was in a position where it could have been deployed, otherwise it goes back into your inventory. However, should a Sentry Gun that has been placed be picked up by the player and the player is killed, the Sentry Gun will disappear if it is not able to be placed.
 * A useful tactic is place the Sentry Gun in a Humvee's gunner position in maps like Afghan. They become hard to spot and are frequently passed by or ignored.
 * If a player is playing spec ops and is killed while holding the sentry gun they will still be carrying it while they are down. Enemies will shoot at it providing great cannon fodder for the other player.
 * Upon reading the writing on the ammo box of a Sentry Gun, one will notice that the writing says "600 Cartridges// 7.62 IW Sentry // Infinity = M1920", followed by a serial number.
 * The idea for the sentry gun could have come from "Aliens", (along with the heartbeat sensor), as an interview showed that Infinity Ward staff watched various movies for inspiration.
 * The combination of the M134 Minigun on the relatively lightweight photographic-style tripods as depicted in the game is simply not feasible in real life, as weight of the weapon(appox.25kg, including the feeding mechanism and electric drive), ammo(1000 rounds of 7.62mm NATO rounds=29kg) and the weight of the targeting system and battery will greatly strains the tripods(of course, it depends on the materials used in its construction), not to mentions the recoil force(up to 150Ib/67.5kg at 3000 rounds per minute-half of the maxium rate of fire of M134) will simply knock the whole set-up off-balance.
 * The first concept of the Sentry was way more technological.
 * In reality, Sentry guns are made for destroying missiles, not attacking enemy targets.
 * The Barrels do not spin in multiplayer, even when firing.