 They all retained their original Japanese caliber of 6.5x50sr.Ordered in mid 1913 from the Huerta government in the standard Mexican military caliber, 7×57mm Mauser, for 50,000 rifles and later for another 25,000 carbines from the Tokyo Artillery Arsenal.They were made to fit the Mexican Mauser model 1895, 1902 or 1910 bayonets.