As World War Two expanded to encompass the whole US economy, it became clear to the Army that some cost cutting measures would be required. One place that was a clear choice was in rimfire .22 caliber training rifles. Since the 1920s, the US had used training and competition rifles from Springfield Armory, built on 1903 rifle receivers and made to the highest quality. These M1922 rifles were very high quality – too high to justify continued use during wartime. Something much cheaper and simpler would be just as good for the abbreviated marksmanship training that was the wartime standard.
The Mossberg company already made and sold the Model 44B rifle, which fit the new US Army needs more closely. It was a simple bolt action rifle with a nice aperture sight, but costing far less than the M1922. After discussion, Mossberg created a new model specifically for the military; the Model 44US. This had a plain birch stock (instead of the commercial walnut), a plastic trigger guard, and a simplified rear sight assembly (although the first batch delivered would use more expensive Lyman sights, until Mossberg was able to put their new model into full scale production).
The Mossberg 44US would remain in production until 1949, successfully serving as a training aid for new recruits and a simple but accurate rifle for shooters after the war.