cartridge (pronounced “thirty-aught-six” or "thirty-oh-six") or 7.62 x 63 mm in metric notation, was introduced to the United States Army in 1906 (hence “06”) and standardized , used until the 1960s and early 1970s. It replaced the .30-03 , 6 mm Lee Navy and .30 US Army (also called .30-40 Krag).