A flexible medical instrument includes an elongate shaft, a jaw tip on the distal end of the elongate shaft and a handle on the proximal end. The elongate shaft includes a coil tube having a distal end fixedly attached to a portion of the jaw tip and a proximal end fixedly attached to a rigid structure at the proximal end of the instrument. The coil tube is disposed within an outer sheath that includes a tubular braid. The elongate shaft and jaw tip are axially rotatable relative to the handle for rotational positioning of the jaws. An actuation element is longitudinally moveable within the shaft to open and close the jaws. The sheath prevents or restricts expansion of the coil tube during pushing of the actuation element.