Call Of Duty 4: Modern Warfare
The grip is a vertical foregrip that offers reduced recoil when a weapon is fired in full-automatic mode. It is only available on LMGs and shotguns. This is unlocked for LMGs after 75 kills and shotguns after 50 kills. Using this attachment, however, will replace Perk 1.
 Modern Warfare 2
The grip is available on shotguns and LMGs. It reduces vertical recoil and does not replace any perk slots.
 Call Of Duty: Black Ops
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