While the US never adopted a significant variation of the M1 Garand (excluding sniper models), testing continued on new iterations and features throughout the war. By the time the war ended, the US military had some specific ideas about what it wanted in a new service rifle. That being, something lighter, capable of automatic fire, and to have one single platform replace the M1 Carbine, M3A1 Grease Gun, M1 Garand, and M1918A2 BAR. New rifles to meet these requirements were developed by Springfield, Remington, and Winchester, ultimately competing against the FN FAL for US service use. The Springfield T44E4 won out (barely) and was adopted on May 1, 1957 at the M14 rifle.

Production of the M14 was plagued by problems, largely due to quality control lapses. Early in production there were heat treatment problems that led to sheared looking lugs and broken receivers. Once those were addressed, the main problem because one of accuracy, with a shocking number of M14s failing to meet the 5.6 MOA minimum accuracy standard. Ultimately production ended in 1963 with 1.38 million M14s produced, and the M16 took over as the new American service rifle.