A firearm grip with selector switch lock includes a handgrip for engaging a firearm receiver having a selector switch. A switch engagement unit is positioned within the handgrip. The switch engagement unit including a motor, piston, spring and detent for selectively engaging the selector switch of the receiver to which the handgrip is located. An RFID interrogator is positioned within the handgrip and communicates with a portable RFID chip. Upon detecting the presence of the RFID chip, the switch engagement unit moves the piston to the retracted position for manual free operation of the selector switch. Upon detecting the RFID chip is not within the proximity of the handgrip, the switch engagement unit moves the piston to the extended/SAFE position. A replacement selector switch having a torque limiter is provided.