As a company support weapon, the M1919 required a five-man crew: the squad leader; the gunner (who fired the gun and when advancing carried the tripod and box of ammunition); the assistant gunner (who helped feed the gun and carried it, and a box of spare parts and tools);  two ammunition carriers.
The original idea of the M1919 was to allow it to be more easily packed for transport, and featured a light barrel and bipod when first introduced as the M1919A1.
Unfortunately, it quickly became clear that the gun was too heavy to be easily moved, while at the same time, too light for sustained fire.
This led to the M1919A2, which included a heavier barrel and tripod, and could be continuously fired for longer periods.

The M1919A4 weighed about 31 pounds (14 kg), and was ordinarily mounted on a lightweight, low-slung tripod for infantry use.
Fixed vehicle mounts were also employed.
It saw wide use in World War II mounted on jeeps, half-tracks, armored cars, tanks, amphibious vehicles, and landing craft.
The M1919A4 played a key role in the firepower of the World War II U.S. Army.
Each infantry company normally had a weapons platoon in addition to its other organic units.
The presence of M1919A4 weapons in the weapons platoon gave company commanders additional automatic fire support at the company level, whether in the assault or on defense.

The M1919A5 was an adaptation of the M1919A4 with a forward mounting point to allow it to be mounted in tanks and armored cars.
This, along with the M37 and the Browning M2 machine gun, was the most common secondary armament during World War II for the Allies.
The coaxial M37 variant had the ability to feed from either the left or the right of the weapon, and featured an extended charging handle similar to those on the M1919A4E1 and A5.
A trial variant fitted with special sighting equipment was designated M37F.
Another version of the M1919A4, the M1919A6, was an attempt to make the weapon into a true light machine gun by attaching a bipod, buttstock, carrying handle, and lighter barrel (4 lb (1.8 kg) instead of 7 lb (3.2 kg)).
The M1919A6 was in fact heavier than the M1919A4 without its tripod, at 32 lb (15 kg), though its bipod made for faster deployment and enabled the machine gun team to dispense with one man (the tripod bearer).
The A6 version saw increasing service in the latter days of World War II and was used extensively in Korea.
While the modifications were intended to make the weapon more useful as a squad light machine gun, it was a stopgap solution.
Even though it was reliable, it proved somewhat impractical for its intended role.
While the 31 lb M1919A4 had a crew of two or more to carry the gun and the 14 lb (6.4 kg) tripod, one M1919A6 gunner was expected to carry and deploy the 32.5 lb (14.7 kg) gun by himself.

In the late 1950s, an M1919 designed for remote firing via a solenoid trigger was developed for use in the XM1/E1 armament subsystem was designated M37C. The US Navy later converted a number of M1919A4s to 7.62mm NATO chambering and designated them Mk 21 Mod 0; some of these weapons were employed in Vietnam in riverine warfare patrols.

From the 1960s until the 1990s, the Israel Defense Forces (IDF) used ground tripod and vehicle-mounted M1919A4 guns converted to 7.62 mm NATO on many of their armored vehicles and M3 personnel carriers.
Israel developed a modified link for these guns due to feeding problems with the original US M1 link design.
The improved Israeli link worked with .30 caliber, 7.62 mm NATO and 8×57 mm cartridges.
As a company support weapon, the M1919 required a five-man crew: the squad leader; the gunner (who fired the gun and when advancing carried the tripod and box of ammunition); the assistant gunner (who helped feed the gun and carried it, and a box of spare parts and tools);  two ammunition carriers. The original idea of the M1919 was to allow it to be more easily packed for transport, and featured a light barrel and bipod when first introduced as the M1919A1. Unfortunately, it quickly became clear that the gun was too heavy to be easily moved, while at the same time, too light for sustained fire. This led to the M1919A2, which included a heavier barrel and tripod, and could be continuously fired for longer periods.
The M1919A4 weighed about 31 pounds (14 kg), and was ordinarily mounted on a lightweight, low-slung tripod for infantry use. Fixed vehicle mounts were also employed. It saw wide use in World War II mounted on jeeps, half-tracks, armored cars, tanks, amphibious vehicles, and landing craft. The M1919A4 played a key role in the firepower of the World War II U.S. Army. Each infantry company normally had a weapons platoon in addition to its other organic units. The presence of M1919A4 weapons in the weapons platoon gave company commanders additional automatic fire support at the company level, whether in the assault or on defense.
The M1919A5 was an adaptation of the M1919A4 with a forward mounting point to allow it to be mounted in tanks and armored cars. This, along with the M37 and the Browning M2 machine gun, was the most common secondary armament during World War II for the Allies. The coaxial M37 variant had the ability to feed from either the left or the right of the weapon, and featured an extended charging handle similar to those on the M1919A4E1 and A5. A trial variant fitted with special sighting equipment was designated M37F.
Another version of the M1919A4, the M1919A6, was an attempt to make the weapon into a true light machine gun by attaching a bipod, buttstock, carrying handle, and lighter barrel (4 lb (1.8 kg) instead of 7 lb (3.2 kg)). The M1919A6 was in fact heavier than the M1919A4 without its tripod, at 32 lb (15 kg), though its bipod made for faster deployment and enabled the machine gun team to dispense with one man (the tripod bearer). The A6 version saw increasing service in the latter days of World War II and was used extensively in Korea. While the modifications were intended to make the weapon more useful as a squad light machine gun, it was a stopgap solution. Even though it was reliable, it proved somewhat impractical for its intended role. While the 31 lb M1919A4 had a crew of two or more to carry the gun and the 14 lb (6.4 kg) tripod, one M1919A6 gunner was expected to carry and deploy the 32.5 lb (14.7 kg) gun by himself.
In the late 1950s, an M1919 designed for remote firing via a solenoid trigger was developed for use in the XM1/E1 armament subsystem was designated M37C. The US Navy later converted a number of M1919A4s to 7.62mm NATO chambering and designated them Mk 21 Mod 0; some of these weapons were employed in Vietnam in riverine warfare patrols.
From the 1960s until the 1990s, the Israel Defense Forces (IDF) used ground tripod and vehicle-mounted M1919A4 guns converted to 7.62 mm NATO on many of their armored vehicles and M3 personnel carriers. Israel developed a modified link for these guns due to feeding problems with the original US M1 link design. The improved Israeli link worked with .30 caliber, 7.62 mm NATO and 8×57 mm cartridges.
M1919 Browning machine gun