Shotgun (attachment)

The Masterkey Shotgun is a weapon attachment in Call of Duty: Modern Warfare 2 and Call of Duty: Black Ops. It is an under-barrel pump-action shotgun compatable with all in-game assault rifles. It is attached in a similar manner to the Grenade Launcher. The Masterkey is pumped everytime it is selected from the inventory on the D-Pad.

Single Player
It is available in the single player mission "Wolverines!" on a SCAR-H with a Red Dot Sight. It is also seen as the attachment for many Ultranationalist and Brazilian Militia weapons (such as the FAL and the AK-47).

Multiplayer
In Multiplayer, it is unlocked for assault rifles by getting 20 kills with the Grenade Launcher. It is pump-action with a four round magazine, and an ammo reserve of 20 shells. If put onto a weapon with limited close quarters effectiveness like the 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 (including One Man Army). 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 most of them must hit in order to ensure a one shot kill. While moving, the crosshairs grow slightly larger, unlike other shotguns. This shotgun has by far the longest range of all of the shotguns, with its pellets traveling more than double the distance of the Model 1887's. However, at such ranges it will take multiple shots to kill a target, making it fairly ineffective. The pump speed is slightly faster than the speed of the SPAS-12's pump, making up for the low damage somewhat.

The Masterkey benefits greatly from both Stopping Power and Steady Aim. Steady Aim provides a tighter hip spread, meaning it can focus in more on its target and increase its already enormous range. However, it is not a one hit kill unless in a very short range, which is enough to stop many players using it. Stopping Power gives each pellet an individual damage boost, which allows for a massive overall increase in potential damage if multiple pellets hit, as well as increased one-shot kill range.

Many players using the Masterkey damage enemies with their primary weapon and then switch to the shotgun to finish them off when they don't have time to reload. Another common tactic is to equip it while moving indoors and then switch back to the primary weapon while outside.

Some players that do use the Masterkey shotgun attachment often use it to clear rooms if their primary assault rifle is not good in close quarters (e.g. SCAR-H, M16A4, FAMAS, FAL, and ACR).

It is advisable to use this attachment in Hardcore modes, especially in Hardcore Search and Destroy.

In Hardcore modes, when combined with Stopping Power and Steady Aim, the shotgun attachment becomes easily the best shotgun available, as Hardcore's reduced health practically guarantees a one-shot kill, and even at longer distances two shots is the maximum it takes to kill an opponent. This also frees up the secondary weapon slot.

Call of Duty: Black Ops
The Masterkey shotgun was seen in a quick preview of the new Create-A-Class for Call of Duty: Black Ops, and is available to the player for 750 CoD Points. It is currently only known to be compatible with certain assault rifles.

Trivia

 * When the player switches to the shotgun from the gun it is attached to, they pump it. However, when the player switches to the shotgun from their secondary, they do not pump it.
 * When used along with a Heartbeat Sensor the majority of the Sensor's screen is hidden from the player's field of view (when the shotgun is out) for all weapons except for the M16A4, M4 Carbine, and the F2000 - the screen is still completely visible with these weapons only, but it still beeps for all weapons.
 * If this attachment is used in conjunction with FMJ via the Bling Perk, both the assault rifle and the shotgun will be affected by FMJ.
 * The Shotgun attachment and the SPAS-12 are the only pump action shotguns in Modern Warfare 2's multiplayer.
 * The character pulls the trigger with his right hand that is covered by the rest of the gun when firing the shotgun.
 * The Shotgun attachment is the only attachment that will say "with" after the gun name (Eg: "ACR with shotgun").
 * Shotgun kills will be counted as kills for the weapon it is attached to and will add to Marksman challenges. This also applies for the Grenade Launcher and Tactical Knife.

Video
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Video demonstrating the extremely effective range of the shotgun attachment, as well as its low damage