[en] A systematic investigation of crystallographic and magnetic properties of nitride R₃Fe_29-xV_xN₄ (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy) has been performed. Nitrogenation leads to a relative volume expansion of about 6%. The lattice constants and unit cell volume decrease with increasing rare-earth atomic number from Nd to Dy, reflecting the lanthanide contraction. On average, the Curie temperature increases due to the nitrogenation to about 200 K compared with its parent compound. Generally speaking, nitrogenation also results in a remarkable improvement of the saturation magnetization and anisotropy fields at 4.2 K and room temperature for R₃Fe_29-xV_xN₄ compared with their parent compounds. The transition temperature indicates the spin reorientations of R₃Fe_29-xV_xN₄ for R Nd and Sm are at around 375 and 370 K which are higher than that of R₃Fe_29-xV_x for R = Nd and Sm 145 and 140 K, respectively. The magnetohistory effects of R₃Fe_29-xV_xN₄ (R = Ce, Nd, and Sm) are observed in low fields of 0.04 T. After nitrogenation the easy magnetization direction of Sm₃Fe_26.7V_2.3 is changed from an easy-cone structure to the b-axis. As a preliminary result, a maximum remanence B_T of 0.94 T, an intrinsic coercivity μ₀H_C of 0.75 T, and a maximum energy product (BH)_max of 108.5 kJ m^-3 for the nitride magnet Sm₃Fe_26.7V_2.3N₄ are achieved by ball-milling at 293 K. (author)