Introduction. The existing criteria for the pairing of traces on shot bullets can not be considered satisfactory. They turn out to be too strict, or do not take into account the identifiable information about the structure of the coincident traces. Therefore, today expert makes categorical conclusion about the identity of the compared traces mainly on bases on his own experience without assessing the probability of a random realization of this event. In this paper, a technique for estimation of the uniqueness of the route complexes in compared traces is considered. In general, the solution of this problem allows us to objectify the expert conclusions. Theoretical analysis. In work the model describing the structure of the routes displayed on the surface of a shot bullet is proposed. On the basis of this model, a method for assessment of the probability of a random coincidence of the routes (the uniqueness of the complexes of coinciding routes) is proposed. Priority list of the similarity of traces is proposed to be formed on the basis of an assessment of the uniqueness of complexes of coincident routes. Empirical analysis. The results of applying the proposed methodology using the proposed pairing criterion are presented. We used two models of weapons: AKM and Makarov pistol. Results. Comparison of test paired and unpaired traces with an assessment of the uniqueness of complexes of coincident routs showed the effectiveness of the proposed methodology and the objectivity of assessing the degree of similarity of the traces.