M16 or M-16 may refer to:
The M16 rifle, officially designated Rifle, Caliber 5.56 mm, M16, is a United States military adaptation of the ArmaLite AR-15 rifle. The original M16 was a select-fire, 5.56×45mm rifle with a 20-round magazine.
In 1963, the M16 entered United States Military service and was deployed for jungle warfare operations during the Vietnam War. In 1969, the M16A1 replaced the M14 rifle to become the U.S. military's standard service rifle. The M16A1 improvements include a bolt-assist, chromed plated bore and a new 30-round magazine. In 1983, the USMC adopted the M16A2 rifle and the U.S. Army adopted it in 1986. The M16A2 fires the improved 5.56×45mm NATO (M855/SS109) cartridge and has a new adjustable rear sight, case deflector, heavy barrel, improved handguard, pistol grip and buttstock, as well as a semi-auto and three-round burst only fire selector. Adopted in 1998, the M16A4 is the fourth generation of the M16 series. It is equipped with a removable carrying handle and Picatinny rail for mounting optics and other ancillary devices.
The Eighth and Ninth Streets Crosstown Line is a public transit line in Manhattan, New York City, United States, running mostly along Eighth Street, Ninth Street, Tenth Street, and Christopher Street through the West Village, Greenwich Village, and East Village. Originally a streetcar line, it is now the M8 bus route, operated by the New York City Transit Authority.
The M8 begins at the intersection of Christopher and West Streets, on the west side of Manhattan. From West Street to Greenwich Avenue, the bus runs west along Christopher Street and east along West 10th Street. At Greenwich Avenue, the bus runs west along West 9th Street and east along West 8th Street. These become East 9th and East 8th Streets, respectively, east of Fifth Avenue (east of Third Avenue, East 8th Street is known as St. Mark's Place). At Avenue A, both directions cross over to East 10th Street to avoid Tompkins Square Park. The route terminates on East 10th Street, just east of Avenue D.