Shotgun (attachment)

The Masterkey Shotgun is a weapon attachment in Call of Duty: Modern Warfare 2. It is an under-barrel pump-action shotgun known as the Masterkey, based on the Remington 870MCS developed originally for the M16 assault rifle. It is attached under the barrel of a weapon in a similar manner to grenade launchers.

In-game
In Multiplayer it is unlocked for Assault Rifles by getting 20 Kills with the mounted grenade launcher. It is pump-action with a four round magazine, and a capacity of 20 shells. If put onto a weapon with limited close quarters effectiveness like FAL, FAMAS, ACR, or M16A4, or a weapon that has a small magazine, like the SCAR-H, the custom class becomes more versatile while still allowing for a secondary weapon. This attachment is not often used by players and can allow the user to surprise enemies. It is also faster to switch to this attachment than it is to switch to any secondary weapon other than a handgun. Unlike most secondary shotguns which fire eight pellets per shot, the Masterkey fires only six pellets meaning the enemies' body will have to take up a sizable amount in order to ensure a one shot kill. While moving, the crosshairs grow slightly larger, unlike other shotguns. This is unusual because none of the other shotguns lose hip accuracy while moving. This shotgun has by far the longest range of all of the shotguns, with its pellets traveling more than double the range of the Model 1887. However, at such ranges it will take multiple shots to kill a target, making it fairly ineffective. However, the pump speed is slightly faster than the speed of the SPAS-12's, making up for the low damage. The Masterkey benefits greatly from both Stopping Power and Steady Aim because Steady Aim provides a tighter hip spread meaning the Masterkey can focus in more on its target and increase its already enormous range. Being pump-action the Masterkey is mainly for single engagement only and as such, Steady Aim would be recommended for single targets.

However, the Masterkey is more of a 'last resort' type shotgun in multiplayer: as mentioned before, it only fires 6 pellets and not 8 meaning that it is unlikely to kill with one shot, making it less of a stand-alone shotgun compared to the other shotgun secondaries. A good tactic to use the Masterkey however is to damage an enemy and finish them off with the shotgun. Usually in a 'cover to cover' situation the enemy either throws a grenade or rushes towards the player to knife them making for a huge surprise once the enemy has found the player. Likewise the player can damage an enemy and rush to the enemies' cover after the enemy has thrown a grenade and take them out with ease due to the range that the shotgun has.

Trivia

 * It is most likely intended to be a KAC Masterkey, although other companies such as Ciener and Serbu produce similar items.
 * This is probably the least used attachment of all.
 * The Masterkey is primarily designed for door breaching (Hence the name 'Master Key'). It was not intended for anti-personnel use.
 * The Masterkey was designed to attach to the M16 and M4 series of rifles, and is not compatible with other rifles, such as the TAR-21 and AK-47.
 * When the player switches to the Shotgun for the first time in the current life, the player's character cycles the action. In reality, this would eject a round, wasting ammunition or to chamber a new shell.
 * A good tactic is to use the Masterkey Shotgun on any assault rifle, when secondary weapon is a launcher, especially the Stinger, because the player will lose usefulness in close combat as the Stinger as a secondary means that a shotgun/machine pistol cannot be used.
 * It is a good idea to attach this to a medium-ranged weapon, so you can use this in close range, saving your rifle ammo.
 * This is often contrasted to the M203 as the grenade launcher provides long-range suppressive abilities, while the Shotgun provides additional close range firepower.
 * When used along with a Heartbeat Sensor the majority of the Sensor's screen is hidden from the player's field of view, but still beeps.
 * In Campaign mode the Shotgun has a capacity of 7 rounds. In Multiplayer, it holds 4 rounds; this was ostensibly done to preserve game balance.
 * If this attachment is used in conjunction with FMJ via the Bling Perk, both the assault rifle and the Masterkey will be affected by FMJ.
 * The Masterkey and the SPAS-12 are the only pump action shotguns in multiplayer.
 * Due to the fact the M203 is unlocked first, has a larger damage spread, and that they both compete for the same slot, it is seen much more often than the Masterkey.
 * The character never pulls the trigger when firing the shotgun.
 * It is more useful in hardcore modes where it is only 1-3 hit kill, with it's long range.
 * If using Bling on the FAL if you attach a silencer and the Masterkey shotgun and fire the Masterkey it will not show up on the radar.

Video
thumb|left|300px|Video demonstrating the extremely effective range of the shotgun, as well as its low damage