For the FCC, challenging requirements are set for the extraction septum magnets. A scaled up LHC-like beam dump system architecture is not attractive in terms of low maximum field, lattice space requirements and power consumption. To address these challenges whilst respecting the requirements for the reliability and availability of the system, a high field massless septum with a target field of 2 T offers several advantages. This paper presents a study of the so-called “Pacman” massless septum design. The field quality, maximum obtainable field, the leak field limits and the effective shielding of the circulating beams are described. The achieved performance is compared to that of an alternative, simpler ironless design with lower field.