To expand capacity beyond Springfield, the War Department used an “educational order” to teach a commercial firm how to make the M1 rifle to military standards. Winchester’s March 1939 contract was a key step toward mass production because it created a second production line and pushed parts standardization between makers.
By 1939, the U.S. Army’s M1 rifle program at Springfield Armory was still building output and learning how to manufacture the new design at scale. This prewar ramp mattered because the M1 was more complex than earlier bolt-action rifles, so production methods had to mature before wartime demand hit.
Even before the initial training run was finished, Winchester was offered a much larger contract for M1 rifles. This move signaled that the U.S. was planning for high-volume procurement and needed industry, not just a government armory, to meet future requirements.
In 1940, Springfield Armory increased capacity with new facilities and improved production practices as defense budgets rose. These changes helped convert the M1 from a peacetime program into a high-throughput manufacturing operation ready for continuous, multi-shift work.
Springfield adopted an improved gas system (the “gas port” design) to replace the earlier “gas trap” system, which was more complicated and less suited to efficient manufacturing. This technical change mattered for mass production because it improved reliability and supported faster, more consistent assembly and maintenance.
Winchester completed and delivered its first M1 rifles in late 1940, proving the rifle could be built outside Springfield Armory. This was a turning point because it expanded total national capacity and reduced the risk of relying on a single producer as the U.S. moved closer to war.
After the attack on Pearl Harbor, the U.S. entered World War II and urgently needed to equip rapidly expanding forces. M1 production became a round-the-clock effort, and output increases were directly tied to the Army’s ability to field infantry units with a standard semi-automatic rifle.
As labor needs grew, Springfield hired more women into roles across M1 manufacturing, from heavy industrial work to stock-making. This workforce shift helped sustain higher production rates and illustrates how mass production depended not only on machines, but also on major changes in labor organization.
By late 1942, Springfield Armory’s cumulative output reached the one-million milestone, showing how quickly production scaled after U.S. entry into the war. Milestones like this mattered because they reflected the industrial capacity needed to arm new divisions and replace battlefield losses.
As Allied operations intensified in 1944, M1 manufacturing reached very high monthly output to support forces in Europe and the Pacific. The production peak shows how rifle manufacturing, ammunition supply, and logistics were coordinated as part of total war mobilization.
Germany’s surrender ended major combat in Europe, changing priorities from replacing losses in that theater to finishing the war against Japan. For M1 production, the transition meant reassessing procurement needs while maintaining enough output to support ongoing operations and occupation requirements.
Japan’s formal surrender effectively ended World War II and marked the close of the M1’s main wartime production surge. By the end of the war, Springfield had produced millions of M1 rifles and Winchester had added hundreds of thousands, showing how mass production helped equip U.S. forces at global scale.
Mass production of the M1 Garand rifle for the U.S. military (1939-1945)