In the 1960s, the South Korean armed forces relied completely upon military support from the United States to supply its small arms, consisting mostly of M1 Garands and M1/M2 carbines. Attempts at the time to develop an indigenous rifle were hampered by the country's economic, technological, and industrial shortcomings, and initial attempts never went into production. During South Korean involvement in the Vietnam War, South Korean army soldiers and marines received the more modern M16A1 assault rifle from U.S. military aid, though not enough to arm all active military personnel. With a modern rifle design and rapid economic growth in the 1970s, South Korea began to build the M16A1 under license in 1974.