A gun is a resource that needs to be held by guards to work. Guards are more efficient at ridding your base of intruders while they have a gun. Guns may also be carried by colonists, and visitors, and are usually seen being used by intruders. Guns can be traded with trading ships. They can also be made at an arms workshop with one metal, one bioplastic, and one semiconductor. While on red alert, colonists may pick up a gun if all your guards have been overwhelmed by intruders.