The M14 is an American-designed 7.62×51mm NATO battle rifle, developed in 1954 by Earle Harvey and Lloyd Corbett at Springfield Armory, adopted by the U.S. military in 1959. Its design was heavily based on the earlier M1 Garand, but uses standard 20-round detachable magazines instead of 8-round internal one and select-fire capability.
It began to be supplanted in 1963 by the M16 rifle, eventually being fully adopted into the U.S military by 1969. It continues to be used in secondary (marksman) roles due to its firepower, longer range and accuracy.
This tag implicates battle_rifle (learn more).