The chemical order in single crystal samples of Ni2MnxV1−xSn has been estimated for x = 1.0, 0.8, and 0.6 by elastic neutron diffraction. The samples were long thin crystals with transverse dimensions less than 1 mm. Extinction was a problem even for these small cross-section samples. The data were fitted to a model that allowed for chemical disorder. All samples were highly ordered. Slight amounts of disorder, 4% or less, were sufficient to explain the data.