The Focus in the present work is placed on the γ phase and how small chemical changes affect its phase stability. In the first place, the composition of the γ phase in the ERBOCo-1 superalloy was determined by means of atom probe tomography and an alloy with this composition was prepared. In the first series, the concentration of one of the major elements (e.g. Cr) was reduced by ~5 at.% and compensated by increases in the concentrations of the other three major elements such that the ratios between them remained constant. From this composition, two series consisting of four additional alloys were delineated. In the second alloy series, the compositions of the first series were simplified to quaternary CrCoNiW alloys such that the ratios between major elements remained the same. After the long term anneals the microstructure and chemical composition of all specimens was investigated by means of X-ray diffraction, scanning and transmission electron microscopies, and energy dispersive X-ray spectroscopy.