Thermodynamically stable nanocrystalline Sm2Fe15Ga2C2 powders were prepared by intense ball milling of homogenized and coarsely ground ingots, and a subsequent annealing of the powders in an argon atmosphere. Such processing results in magnetically isotropic material with a room‐temperature coercivity μ0JHc of up to 1.2 T. Scanning electron microscopy observations suggest a homogeneous microstructure, and combined with Scherrer formula estimations, an average grain size of 3) of the theoretical density (7.8 g/cm3) and a coercivity of 1.3 T.