The M16 is a 5.56mm automatic rifle based off of the ArmaLite AR-15. Deployed in 1964 for jungle warfare during the Vietnam War, the M16A1 later replaced the M14 rifle in 1969 as the standard service rifle for the U.S military. Its improvements included a bolt-assist, chrome-plated bore, and a 30-round magazine. While no longer active in the U.S service, it is standard issue in other world armies.