Despite extensive work on machine guns in the years between the world wars, the only new design to emerge was the Johnson cal. .30 Model 1941 Light Machine Gun, from Johnson Automatics Inc. the company that produced the Johnson .30 cal. Semiautomatic Rifle. Col. Melvin M. Johnson, Jr., a captain in the Marine Reserve, was a gifted inventor whose company produced two models of the machine gun, the M-1941 and the M-1944, with only about 9,500 issued in total.
Marine in gas mask carrying M-1941 Johnson light machine gun, New River, NC, May 1942.
Johnson Light Machine Gun, Models of 1941 and 1944
The Johnson Light Machine Gun, Models of 1941 and 1944, were issued, like the Johnson .30 cal. Semiautomatic Rifle, primarily to the USMC and Special Forces including the joint Canadian-American 1st Special Service Force (FSSF) in the ETO. FSSF was issued the Johnson Machine Gun in 1943.
The Johnson Light Machine Gun had a front blade sight and a rear folding aperture sight. The Johnson Model 1941 fired Army standard .30 cal. cartridges from a 20-round box magazine with a rate of fire of 400-450 rounds per minute.
The Johnson Model 1944 modification of the Model 1941 did not change the action but replaced the bipod by a monopod and had a tubular metal stock instead of wood.
References for the M-1941 & M-1943 Johnson Machine Guns
There are many fine websites that have additional information on this
topic, too many to list here and too many to keep up with as they come and go.
Use this Google web search form to get an up to date report of what's out there.
For good results, try entering this: m1941 johnson. Then click the Search button.