The proposed experiment forms a part of a joint study by M. Rahman, an ILL PhD thesis student, and J. Brokx, a CDT thesis student supported by ISIS. In the proposed experiment, we intend to start the process of formalising the methodology for dealing with and ultimately quantifying the errors specific to determining residual stress in the microstructures typically found in dissimilar metal welds by simplifying the measurements with idealised samples. In particular, we plan to investigate the issue of pseudo-strains experimentally in association with voids and uneven distribution of large grains within a diffracting gauge volume. In addition, the experimental data will be used for the validation of the McStas simulation studying the pseudo-strain effects due to large grains or local texture.