However, by and large the most common variant of the series was the M1919A4.
Production blueprints of the new variant were complete in late 1936, and slow-scale production soon followed.
The driving force behind the development of this variant was the suffering reliability of the 18-inch barrel of previous versions, which did not produce enough recoil to cycle the action reliably.
The bull barrel was made much thicker and was lengthened to 24 inches like the M1917.
Various other small adjustments to the design were made, such as moving the front sight from the barrel jacket to the receiver, which made it easier to mount the gun on vehicles.
The design of the barrel jacket was changed to include circular holes instead of long slits of earlier models, and a recoil booster in the muzzle end improved reliability.
The recoil buffer assembly was also a new addition to the design between A3 and A4 development, designed to reduce the impact of the bolt hitting the backplate.

The M1919A4 was used in both fixed and flexible mounts, by infantry and on vehicles.
It was also widely exported after World War II and continues to be used in small numbers around the world.
Two variants were developed specifically for vehicular use, the M1919A5, with an extended charging handle, and the M1919A4E1, a sub-variant of the M1919A4 refitted with an extended charging handle developed in the 1950s.
However, by and large the most common variant of the series was the M1919A4. Production blueprints of the new variant were complete in late 1936, and slow-scale production soon followed. The driving force behind the development of this variant was the suffering reliability of the 18-inch barrel of previous versions, which did not produce enough recoil to cycle the action reliably. The bull barrel was made much thicker and was lengthened to 24 inches like the M1917. Various other small adjustments to the design were made, such as moving the front sight from the barrel jacket to the receiver, which made it easier to mount the gun on vehicles. The design of the barrel jacket was changed to include circular holes instead of long slits of earlier models, and a recoil booster in the muzzle end improved reliability. The recoil buffer assembly was also a new addition to the design between A3 and A4 development, designed to reduce the impact of the bolt hitting the backplate.
The M1919A4 was used in both fixed and flexible mounts, by infantry and on vehicles. It was also widely exported after World War II and continues to be used in small numbers around the world. Two variants were developed specifically for vehicular use, the M1919A5, with an extended charging handle, and the M1919A4E1, a sub-variant of the M1919A4 refitted with an extended charging handle developed in the 1950s.
M1919 Browning machine gun