The present invention relates to a feeder system for use in metal casting operations utilising casting moulds, and to feeder sleeves and breaker cores for use in the feeder system. There is provided a feeder system for metal casting, the feeder system comprising a feeder sleeve mounted on a breaker core, the feeder sleeve having a first end and an opposite second end, a longitudinal axis extending between the first and second ends, and a continuous sidewall extending generally around the longitudinal axis between the first and second ends, the sidewall defining a cavity for receiving molten metal during casting, and the breaker core defining an open bore therethrough for connecting the cavity to the casting, wherein the first end of the feeder sleeve comprises a base portion which is mounted on the breaker core, and the second end of the feeder sleeve comprises a planar roof portion and a curved or chamfered portion extending around the periphery of the roof portion, for connecting the sidewall and the roof portion.