MIL-R-3285, MILITARY SPECIFICATION: RIFLES, U. S., CALIBER. 30, M1 AND M1C (08 SEPT 1950) [SUPERSEDES ARMY 52-1-21 AND SPRINGFIELD SXS-169]., Rifles shall be semi-automatic,of one type in the following models, as specified(see 6.2) :Rifle U. S., Caliber .30, M1.Rifle, U. S., Caliber .30, M1C.