Actually, if the US practice was similar to that followed in the British Empire, the whole purpose of service rifle competitions was to compete with the current primary-issue service rifle. So, after an "overlap period" (the duration of which may have been specified in the rules, or might have been dictated by the point in time when the '03 reached a certain "issuance level" ) the '03 would have been the mandated rifle for use in such competitions.