The original name of the .50 Caliber Machine Gun is the M2 Browning. The prototype was developed by John M. Browning in 1918 right after WWI when the world was saying farewell to ditch warfare.
The machine gun has been in production since 1921 and more than 3 million units have been produced to date, currently by a plethora of companies most notably General Dynamics, US Ordnance, Manroy Engineering UK, Sabre Defense, etc.
The M2 is crew transportable thanks to a back plate with a spade, trigger, grips and latch release. Furthermore, the gun comes with a flash suppressor and spare barrel assembly making it a portable machine gun compared to other heavy weapons.
The Machine Gun is almost 61.42 inches in length and weighs 84 pounds alone and 128 pounds with its tripod. The bore has a diameter of .50 inches, obviously!