At the beginning of World War II, the British government contracted with the Savage Stevens company in America to build Lee Enfield No. 4 Mk I rifles. In 1941, the United States Government passed the "Lend Lease Act" to supply nations battling the Axis powers with war equipment and material. The British contract for Lee Enfield No. 4 rifles with Savage Stevens was taken over by the U.S. government. Thereafter, the Savage produced Lee Enfield No. 4 rifles were roll marked on the receiver "U.S. Property" and sent overseas to countries as Lend Lease equipment.
During the Savage production of these rifles, changes were made to simplify their production, and the rifle's designation was officially changed to Lee Enfield No. 4 Mk1*.