A series of pure polycrystalline M-type hexagonal ferrite with the formula BaCo_0.5xZn_0.5x Ti_xFe_12-2xO₁₉ (x = 0.0, 0.4, 0.8, 1.2, 1.6, 2.0) has been synthesized and studied by X-ray diffraction and Mössbauer spectroscopy. With increasing substitution the Mössbauer spectra change from magnetically ordered (x = 0) towards magnetically ordered with strong line broadening (x = 0.4 to 1.6) to nonmagnetic (x = 2.0), due to decreasing of Curie temperatures. Differential line broadening and relative area of components indicates that for small values of x, a substitution occurs preferentially in 4f₁ and 4f₂ sites indirectly affecting Fe in the 12k site.