The bulk of metal meteorites consists of the Fe,Ni-alloys kamacite [α-(Fe,Ni), bcc structure] and taenite [γ-(Ni,Fe), fcc structure]. The chemical composition is dominated by Fe and Ni, which make up more than 95%. Nickel is always present with a concentration ranging between 5 and 25%. Previous Time-of-Flight Neutron Diffraction experiments using the INES beamline were carried out aiming to characterize the quantitative amount of the two main phases and their microstructure. The results were useful for the characterization of the samples but also evidenced some anomalous and very interesting trends in lattice paramter values. A possible explanation of this phenomenon requires the presence either of residual stress or of micro-structural phenomena. If confirmed, the presence of residual stresses in iron meteorites would tremendously affect the research on planetary science.