Shotgun (attachment)

The 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 870 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 or M16A4, or weapon's magazine and/or ammo reserve makes difficult to hip-fire (SCAR-H for example) the weapon becomes very potent and versatile whilst allowing a slot for a secondary weapon at the same time. This attachment is relatively rare and allows the user to surprise enemies. It is also faster to switch to the attachment than it is to switch to a secondary weapon (except handguns). Players should notice that the crosshairs grow larger (to a certain extent) as the player is in constant movement. Remaining immobile will instantly reset the crosshairs. This shotgun has by far the longest range, having more than double the range of the SPAS-12 and Model 1887. However, at long ranges, expect to use all 4 shells, if not more, to kill an enemy (in Core modes). Like most shotguns, it works well with Stopping Power and Steady Aim, becoming rival even for M1887 in terms of long range kills, however, Stopping Power has a better effect on a shotgun than steady aim, forcing the player to choose between stopping power and Cold Blooded for Anti-Air class (for example). At close range it is still potent with about the same damage as the Striker, so one well aimed shot can kill, but be prepared to fire multiple rounds to get a kill, if first didn't make it.

Trivia

 * It is most likely intended to be a KAC Masterkey, although other companies such as Ciener and Serbu produce similar items.
 * In real life the Masterkey is for door breaching, not engaging personnel, hence its name.
 * In first person, the player character never has a hand near the trigger, rather on the action, meaning that the player should not be able to fire it, but this was most likely kept to keep the shotgun from having an incredibly slow rate of fire. It is possible that the player has their right finger on the trigger and is supporting the weapon with their forearm.
 * Every time the player switches to the shotgun attachment from the weapon it is attached to he cocks the gun. In reality this would eject a round, wasting ammo.
 * A good tactic is to use 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 you rifle ammo.
 * This is often compared to the M203 as grenade launchers have range, but shotguns can be used in close range.
 * A good tactic is to use the Masterkey to kill enemies in Last Stand. Due to the enemies health in last stand, as long as 1 pellet hits the enemy, even from the weapons maximum range, it will kill the enemy.