The Johnson Automatics, Part II: The Johnson Light Machine Gun

By Frank Iannamico

In addition to his recoil operated semi-automatic M1941 rifle, Melvin Johnson designed and produced a machine gun, the M1941 Light Machine Gun, (H). The (H) designates a horizontal feed magazine. Similar suffixes used on other Johnson designed weapons were: (V) for a vertical fed magazine and ( R ) for a rotary fed design. The magazine fed light machine gun utilized Johnson’s unique recoil operated design, which uses residual chamber pressure and barrel recoil to operate the action. The advantage to the design is the elimination of a conventional gas system to function the weapon. When the weapon is fired the barrel recoils rearward for approximately .5 of an inch. The receiver supports the barrel on two bearing surfaces. A rotary bolt moves rearward locked to the barrel until it is unlocked by being rotated counter clockwise 20 degrees by a caming action between the receiver and bolt. The barrel’s rearward movement is stopped by a shoulder in the receiver, while the bolt continues rearward far enough to pick up a fresh round from the magazine before being pushed forward into the chamber by the recoil spring assembly. The rotating bolt head is locked to the barrel by eight lugs. The recoil spring and buffer are located in the stock. The cyclic rate of the weapon is 550-600 rounds per minute.

As with his rifle, Melvin Johnson’s LMG was only used by the United States military in limited numbers. While the M1941 semi-automatic rifle had the M1 Garand as its main adversary, the LMG competed against the legendary BAR. Unfortunately, development of both Johnson’s weapons were untimely, becoming available only after the Garand and BAR had already been placed in mass production for WWII. The Marine Corps adopted Johnson’s weapons only when the BAR and Garand were not being produced in sufficient numbers to fulfill the wartime demand. The Johnson LMG, like the M1941 semi-automatic rifles, were manufactured for Johnson Automatics by a subcontractor, Cranston Arms of Rhode Island.

In reality the Johnson design had many modern and innovative features. The 1941 Model was much lighter than the BAR at 14.2 pounds with the bipod. Another very important feature, especially for a weapon of its type, was a removable barrel that could be easily replaced in the field. The weapon was select-fire, and fired from a closed bolt in the semi-automatic mode, and fired from an open bolt when in full-auto. The modes of operation: safe-fire and automatic were controlled by a single “change lever”. The overall length of the weapon was 42 inches, while the standard barrel was 22 inches in length. The barrel featured a 4-groove 1 in 10” twist, and according to the operator’s manual, could be replaced “in 5 to 6 seconds.” Mr. Johnson preferred that his weapon be referred to as an “automatic rifle” or “light machine rifle” rather than a “light machine gun.” He often compared his weapon to the 8mm German paratrooper automatic weapon, the FG-42 that could, and often was, fired from the shoulder like a rifle. Johnson wanted to convey that his weapons were not simply “light machine guns” but rather versatile “automatic rifles” that could easily be fired from the shoulder when necessary.

The rear sight on the LMG is a flip up aperture style, calibrated in yards, the sight featured two apertures, the upper one for up to 1,000 yard range and the other (placed 49 MOA lower) designed for barrage fire up to 1500 yards. The adjustable rear sights were supplied to Johnson Automatics by either the Lyman or Marbles Company. The blade style front sight is unusually high, (similar to that of the M16 rifle) because of the “straight line” configuration of the stock. The twenty round capacity, single feed box-style magazine is also unique, as there are no feed lips. The feed lips are machined into the receiver. Also located inside of the receiver is a rotary magazine mechanism similar to that of the Johnson semi-automatic rifle. The box magazine is inserted into the left side of the receiver. The magazine release lever also serves as a cartridge-retaining device to keep the loaded rounds from flying out of the magazine in the absence of conventional feed lips. When the magazine is inserted into the weapon, the magazine support guide hook cams upward on a ramp and releases the cartridges in the magazine. The magazine spring then locks onto a shoulder on the ramp and locks the magazine into place. The cartridges are then fed into the integral magazine inside of the receiver. An additional five rounds could be loaded into the receiver making the total capacity of the weapon 25 rounds. The magazine could be easily recharged while in the weapon via the M1903 rifle stripper clips. The magazine was overly long because of its single stack/single feed design. The magazine body was also easily damaged.

A detachable folding bipod was also featured on the Model 1941 LMG. The bipod is placed well back from the muzzle, allowing the weapon to be traversed over a wide area very quickly. The M1907 sling was often issued with the weapon, as well as a web style sling. A tan color bag type magazine pouch was designed for issue with the Johnson, for carrying the long, curved Johnson magazines. The pouches are extremely rare today.

It has often been reported that 10,000 of the Johnson M1941 Light Machine Guns were manufactured, but the actual number of weapons produced was much less. These were adopted and used during World War Two by U.S. Marine paratroopers and the Marine Raiders in the Pacific Theater, as well as the U.S./Canadian Army First Special Service Force in Italy and North Africa. The Netherlands also ordered a substantial number, but few were delivered before the Dutch East Indies fell into Japanese hands. A few of the light machine guns were believed to be procured and used by the French. Generally the weapon’s performance was acceptable, although there were a few reports that it was too fragile for extreme combat conditions. The long leaf spring extractor was especially prone to failure under extended combat use.

An improved model was introduced in 1944. This version was known as the Model 1944 Johnson Light Machine Gun. Problems and experience from the first design generated the improvements that were incorporated in the 1944 Model. The receiver was redesigned for more positive feed to prevent jamming. A redesigned tubular buttstock was manufactured from Micarta, and the pistol grips were made of plastic, no wood furniture was used on the M1944. A cleaning kit was stored in the lower portion of the stock. The bipod of the earlier model was replaced by an adjustable nine position, folding 1.7 pound integral monopod. When the weapon was fired from the shoulder the folded monopod served as a forearm for the support hand. The weapon weighed a total of 14.7 pounds. The M1944 operator’s manual states that the cyclic rate is variable from 350 to 750 rounds per minute by changing the buffer springs in the stock. The only tool required for field stripping the weapon is a standard 30’06 cartridge. A special 20-inch barrel was offered as an option for cavalry or paratrooper use. The Johnson Light Machine Guns shared many of the same parts used in the M1941 semi-automatic rifle.

Both the Johnson rifle and the light machine gun saw limited service during WWII with the Office of Strategic Services. The OSS found that the Johnson weapons when disassembled were easily concealed and offered a lot of large caliber firepower. Fidel Castro’s troops also used Johnson’s weapons in his revolution against Cuba’s Batista government in 1958-59. Ironically anti-Communist Cuban Guerrillas also used Johnson weapons against Castro in the ill-fated struggle to reclaim their homeland.

Development of the Johnson Light Machine Gun concept continued after WWII, resulting in a Model of 1945 LMG. There was little post war interest and the light machine gun development program was terminated in 1947. In the 1950s the Israelis manufactured a close copy of the Johnson design called the Dror. The Israeli version was chambered in 8mm Mauser and .303 British. Like the Johnson before it the Dror was only manufactured in limited quantities.

Melvin Johnson continued in the firearms business after the war ended. His company specialized in converting military rifles into sporters for hunting. He also offered his M1941 rifles in both sporter and military configurations. Melvin Johnson died in 1965 at the age of 55.

This article first appeared in Small Arms Review V4N7 (April 2001)
and was posted online on June 27, 2014


Comments have not been generated for this article.