Successfully complete the indicated task to unlock the corresponding weapon 
upgrade for the indicated character for use in any replayed mission:

7.62mm sniper rifle gun camera (Graves): Successfully complete the first mission
7.62mm sniper rifle suppressor (Graves): Successfully complete three missions
Automatic shotgun (Graves): Successfully complete eight missions
Flashbangs (Graves and Lang): Successfully complete four missions
HEAT rocket launcher (Lang): Successfully complete the first mission
Incendiary grenade (Lang): Successfully complete five missions
LMG 5.56mm 200-round magazine capacity (Lang): Successfully complete three missions
LMG 5.56mm 25% increased rate of fire (Lang): Successfully complete seven missions
LMG 5.56mm 40mm grenade launcher (Lang): Successfully complete two missions
LMG 5.56mm Foregrip (Lang): Successfully complete nine missions
Proximity mine (Graves): Successfully complete six missions
Shotgun attachment (Graves): Successfully complete two missions