Abstract: Opposed pairs of sockets are formed by the bottom surface of the slip housing and the top surface of the bottom ring of a casing hanger assembly. Vertical holes are provided in the elastomer seal element which is sandwiched between the slip housing and bottom ring. Each pair of sockets and corresponding seal element hole form a socket chamber. Rigid, motion-limiting pins are positioned in the socket chambers. Each pin has side and bottom clearances with the chamber side and bottom walls. The pins are therefore initially free floating, to allow the seal element to move to accommodate oversized casing; but the pins take up the casing load as the slip housing descends and limit its downward travel, thereby preventing excessive compression of the seal element, which can lead to casing damage.