The M1919 pattern has been used in countries all over the world in a variety of forms and under a number of different designations.

The Browning Mk 1 and Mk 2 were older-style Commonwealth designations for the .303 caliber Browning machine guns used on the vast majority of British aircraft of World War II.
The difference between the Mk 1 and Mk 2 versions is unknown, but the weapon visually is quite similar to the AN/M2 aircraft gun.
The post-war designations for these weapons was L3, and they were used by the United Kingdom, Canada, and Australia to designate the fixed (A1) and flexible (A2) versions of the M1919A4 in .30-06 caliber.
L3A3 and L3A4 denoted sear hold-open conversion of previous L3A1s and L3A2s.
The A3 is the modified version of the A1, and the A4 is the modified version of the A2.
The Canadians later adopted a separate designation for 7.62×51mm rechambered M1919A4s for fixed (C1) and flexible (C1A1) applications.
The C5 and C5A1 were product improvements of the previous C1 and C1A1 respectively.

The Rhodesian Air Force used twin Browning Mk 2 models, chambered in the British .303 cartridge, mounted on Alouette III G-Car helicopters as well as modified variants fitted with FN MAG bipods, pistol grips and stocks for ground use.

The Browning was produced by FN-Herstal in Belgium as well, being used in, among others, the Fokker D.XXI and IAR-80/81 fighters.

MG A4 is the Austrian designation for the M1919A4.

MG4 is a South African upgrade of the M1919 in current use with the South African National Defence Force.
The MG4 upgrade was done by Lyttleton Engineering Works, Pretoria.

MG m/52-1 and MG m/52-11 were Danish designations for the M1919A4 and M1919A5 respectively.

The Israel Defense Forces (IDF) used vehicle-mounted M1919A4 guns converted to 7.62mm NATO on many of their armored vehicles.

Ksp m/22 is the Swedish designation for license-built M1919s chambered for 8×63mm patron m/22 cartridges, for aircraft use.

Ksp m/39 is the Swedish designation for M1919A4 license-built by Carl Gustafs Stads Gevärsfaktori chambered in 6.5×55mm and 8×63mm patron m/32, and from about 1975 rebarreled in 7.62×51mm NATO.
Intended for use in tanks and armoured vehicles, it's available with both left- and right hand feeding, the former is used in CV 90.

Ksp m/42 was the Swedish designation for license-built M1919A6 used for infantry support, normally chambered in 6.5×55mm but occasionally in 8×63mm patron m/32, and from about 1975, mostly fitted with barrels in 7.62×51mm NATO.
The Ksp m/42B was a lighter version with bipod and shoulder stock (used in a similar way as the M1919A6), chambered in 6.5×55mm and later in 7.62×51mm.
Even the ksp m/42B proved too heavy, and was replaced by the ksp m/58 (FN MAG).
In the late 1980s, most remaining ksp m/42 was rebuilt into ksp m/39 to be installed into the CV 90s.

The Poles developed a copy of the Browning M1919 chambered for 7.92×57mm Mauser, designated Ckm wz.32, similar to the earlier Ckm wz.30.
The M1919 pattern has been used in countries all over the world in a variety of forms and under a number of different designations.
The Browning Mk 1 and Mk 2 were older-style Commonwealth designations for the .303 caliber Browning machine guns used on the vast majority of British aircraft of World War II. The difference between the Mk 1 and Mk 2 versions is unknown, but the weapon visually is quite similar to the AN/M2 aircraft gun. The post-war designations for these weapons was L3, and they were used by the United Kingdom, Canada, and Australia to designate the fixed (A1) and flexible (A2) versions of the M1919A4 in .30-06 caliber. L3A3 and L3A4 denoted sear hold-open conversion of previous L3A1s and L3A2s. The A3 is the modified version of the A1, and the A4 is the modified version of the A2. The Canadians later adopted a separate designation for 7.62×51mm rechambered M1919A4s for fixed (C1) and flexible (C1A1) applications. The C5 and C5A1 were product improvements of the previous C1 and C1A1 respectively.
The Rhodesian Air Force used twin Browning Mk 2 models, chambered in the British .303 cartridge, mounted on Alouette III G-Car helicopters as well as modified variants fitted with FN MAG bipods, pistol grips and stocks for ground use.
The Browning was produced by FN-Herstal in Belgium as well, being used in, among others, the Fokker D.XXI and IAR-80/81 fighters.
MG A4 is the Austrian designation for the M1919A4.
MG4 is a South African upgrade of the M1919 in current use with the South African National Defence Force. The MG4 upgrade was done by Lyttleton Engineering Works, Pretoria.
MG m/52-1 and MG m/52-11 were Danish designations for the M1919A4 and M1919A5 respectively.
The Israel Defense Forces (IDF) used vehicle-mounted M1919A4 guns converted to 7.62mm NATO on many of their armored vehicles.
Ksp m/22 is the Swedish designation for license-built M1919s chambered for 8×63mm patron m/22 cartridges, for aircraft use.
Ksp m/39 is the Swedish designation for M1919A4 license-built by Carl Gustafs Stads Gevärsfaktori chambered in 6.5×55mm and 8×63mm patron m/32, and from about 1975 rebarreled in 7.62×51mm NATO. Intended for use in tanks and armoured vehicles, it's available with both left- and right hand feeding, the former is used in CV 90.
Ksp m/42 was the Swedish designation for license-built M1919A6 used for infantry support, normally chambered in 6.5×55mm but occasionally in 8×63mm patron m/32, and from about 1975, mostly fitted with barrels in 7.62×51mm NATO. The Ksp m/42B was a lighter version with bipod and shoulder stock (used in a similar way as the M1919A6), chambered in 6.5×55mm and later in 7.62×51mm. Even the ksp m/42B proved too heavy, and was replaced by the ksp m/58 (FN MAG). In the late 1980s, most remaining ksp m/42 was rebuilt into ksp m/39 to be installed into the CV 90s.
The Poles developed a copy of the Browning M1919 chambered for 7.92×57mm Mauser, designated Ckm wz.32, similar to the earlier Ckm wz.30.
M1919 Browning machine gun