when was the 30 round m16 magazine introduced
M16 rifle In 1964, the M16 entered U.S. military service and the following year was deployed for jungle warfare operations during the Vietnam War.[1] In 1969, the M16A1 replaced the M14 rifle to become the U.S. military's standard service rifle.[15][16] The M16A1 improvements include a bolt-assist, chrome plated bore and a new 30-round magazine.[1] In 1983, the U.S. Marine Corps 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.[17][18] Adopted in 1998, the M16A4 is the fourth generation of the M16 series.[19] It is equipped with a removable carrying handle and Picatinny rail for mounting optics and other ancillary devices.[19]
FN P90 The P90 uses a unique horizontally mounted feeding system—patented in the United States—that contributes to the weapon's compact profile and unusual appearance.[12] U.S. Patent 4,905,394 ("Top mounted longitudinal magazine") was awarded in 1990, naming René Predazzer as the sole inventor.[31] The detachable box magazine is mounted parallel to the P90's barrel, fitting flush with the top of the weapon's frame, and it contains 50 rounds of ammunition which lie in two rows facing left, offset 90° from the bore axis.[17] As the cartridges are pushed back by spring pressure and arrive at the rear end of the magazine, they are fed as a single row into a spiral feed ramp and rotated 90 degrees, aligning them with the chamber.[17] The magazine body is composed of polymer, and it is semi-transparent to allow the shooter to see the amount of ammunition remaining at any time.[17]