An insertion device for taking samples within a body. The insertion device includes a trigger housing, an outer sheath assembly, a sampling device, and a resilient member. The trigger housing includes an interior channel in which the resilient member is disposed to urge the outer sheath assembly away from a proximal end of the trigger housing. The outer sheath assembly is disposed within the interior channel of the trigger housing. The outer sheath assembly includes a body and an outer sheath attached to a distal end of the body. The sampling device is removably disposed within the outer sheath assembly and the trigger housing. The sampling device may be a removable biopsy needle assembly which is used to cock the insertion device. The removable biopsy needle assembly may be removed from the insertion device and be replaced by a needle assembly for fine needle aspiration.