The M1941 rifle used the energy from recoil to operate the rifle. As the bullet and propellant gases moved down the barrel, they imparted a force on the bolt head that was locked to the barrel. The barrel, together with the bolt, moved a short distance rearward until the bullet left the barrel and pressure in the bore had dropped to safe levels. The barrel then stopped against a shoulder allowing the bolt carrier to continue rearward under the momentum imparted by the initial recoil stage. The rotating bolt, which had eight locking lugs, would then lock the bolt. Following, a cam arrangement then rotated and unlocked the bolt to continue the operating cycle.One disadvantage of this design was its impact on the use of a bayonet, as the complex movements of the barrel would be subject to unacceptable stress when a bayonet thrust was used. The Johnson rifle utilized a unique 10-round rotary magazine and a two-piece stock, the weapon using the same 5 round stripper clips used by the M1903 Rifle.
This system had some advantages over the M1 Rifle, including less perceived recoil and greater magazine capacity. Unfortunately, the Johnson's recoiling barrel mechanism resulted in excessive vertical shot dispersion that was never fully cured during its production life, and was prone to malfunction when a bayonet was attached to the reciprocating barrel. The Johnson also employed a number of small parts that were easily lost during field stripping. Partially because of lack of development, the M1941 was less rugged and reliable than the M1, though this was a matter of degree and was not universally opined amongst those that had used both weapons in combat.
Melvin Johnson campaigned heavily for the adoption of the Johnson rifle by the U.S. Army and other service branches. However, after limited testing, the U.S. Army rejected Johnson's rifle in favor of the M1 rifle developed by Springfield Armory. The M1941 was ordered by the Netherlands for issue to the KNIL in the Dutch East Indies, but only a few rifles were shipped to the Dutch East Indies before the Japanese invaded. At this time, the U.S. Marine Corps found itself in need of a modern fast-firing infantry rifle, and acquired some rifles from the Dutch East Indies shipment for issue to its Paramarine battalions then preparing to deploy for action in the Pacific theatre. By all accounts, the M1941 performed acceptably in combat with the Marines in the early days of the Pacific fighting.
Weapon serial number A0009 was issued to USMC Captain Robert Dunlap, of Monmouth, Illinois, and he carried it into combat in the battle for Iwo Jima, beginning 19 February 1945. Captain Dunlap was awarded the Medal of Honor for his actions in that battle, and he retained and displayed the weapon until his death in 2000. He praised the rifle and credited it with saving his life and the lives of others.
Despite repeated requests to adopt the rifle by the Marine Corps, the Johnson rifle also lacked the support of US Army Ordnance, which had already invested considerable sums in the development of the M1 and its revised gas operating system, then just going into full production. Johnson was successful in selling small quantities of the M1941 Johnson Light Machine Gun to the U.S. armed forces, and this weapon was later used by both Para-Marines and the Army's First Special Service Force. Additionally, in April 1944, the United States War Department offered the Free French military the use of approximately 10,500 Johnson rifles and 1,500 Johnson light machine guns; these guns were from undelivered Dutch/Netherlands contracts taken over by the United States Government in 1942. The French accepted them and issued them to their "Sovereignty troops" (i.e. units composed mainly of Europeans).