A feeder insert for use for the casting of metals into casting molds, having a mold body (6) and a supply element (4) which delimit the feeder cavity (10) for receiving liquid metal, wherein the supply element (4) has a passage opening (26) for the liquid metal, and wherein the mold body (6) is movable in a feeder longitudinal direction relative to at least one part of the supply element (4), characterized in that the supply element (4) has a deformation region which is designed to trim in at least in sections in at least a first phase of a relative movement of the mold body (6) in the feeder longitudinal direction and in the direction of the supply element (4).