Masterkey

The Masterkey is an attachment in BlastGen. It is the eleventh attachment unlocked and the final attachment unlocked for assault rifles.

Overview
The Masterkey is an underbarrel shotgun that can only be attached to assault rifles. It carries 8 shells at a time and is pump action. It does not come with any reserve ammo unlike the Grenade Launcher, however ammo can be replenished for it by picking up ammo from weapons with Masterkeys attached. It fires 8 pellets per shot, like normal shotguns, with each pellet dealing about 20 damage, meaning 5 pellets must hit to score a one shot kill. It can manage to net one shot kills at up to 20 metres and anything further than that, it will cease to deal any damage. It is a very effective alternative to a shotgun, as it will save the player a perk slot while giving them a underbarrel shotgun.

However, when the Masterkey is attached, the player's Lethal slot will be replaced by it, as the Masterkey must be fired by using the lethal equipment button. This makes the Masterkey a poor option if players like running classes that revolve around explosives. However, players who rush often may find this a useful attachment. The attachment fits well on the M16 as it increases its close range effectiveness since it is a burst weapon that does not compete well in close range. Overall it is a great attachment, though it is often overlooked at times. Nevertheless, it can be an effective weapon in the right situations.

Campaign
The only instance where the Masterkey is seen is if the player kills Arnett in Epilogue, to which he will drop an UMP-5 with a Reflex Sight and a Masterkey. The Masterkey has infinite reserve ammo, a unique M26 MASS model, and has a different firing sound than in Multiplayer. A unique black ACR with a Masterkey and Suppressor can be obtained via console commands in the mission Infiltration, and again it has infinite reserve ammo but has the same firing sound from Multiplayer.

Zombies
Although rare, the Masterkey can be a random attachment attached to an assault rifle from the Strongbox or as a random attachment dropped by an Armored Zombie occasionally. It deals a gargantuan 900 damage per shot, which can one shot kill all zombie types until around round 24. When an AR is upgraded with the Masterkey attached, it will double the damage of it, making it deal a mind numbing 1800 damage per shot, where it will remain a one shot kill until round 40, making it a very promising attachment. It always starts with 8 shells, shares ammo with shotguns, and has no damage multipliers.

Trivia

 * The Masterkey is modelled after a traditional KAC Masterkey.
 * At some point, LMGs, the UMP-5, and the HK418 were all supposed to be able to equip the Masterkey, but it was scrapped before the game's full release. The Masterkey on LMGs was going to use the AR's model while the two SMGs were going to use the M26 MASS model.