In the US, for civilians, it is a Class III firearm that requires registration with the Federal government.
Miniguns are classified weapons
45 caliber Machine Gun and 50 caliber machine gun
50. caliber machine gun....period
Phosphating
See link below to the US Army Field Manual on the Caliber .50 M2 Machine Gun.
50 caliber for US forces
The highest caliber machine gun in standard use is the .50 Cal. Gatling guns are used in 20mm caliber. XXXXXXXXX Russia and China use a heavy machine gun larger than the .50 cal BMG- it is the Vladmirov KDV (for the Russians), in caliber 14.5mm x 115.
1000
1500-2000 meters
Russian .60 caliber. There is also a Chinese version. More powerful than the US .50 Browning, it is a true Heavy machine gun.
The 12.7x99mm/Caliber .50 cartridge used in rifles such as the Barret M82, MacMillan Tac-50, and others, as well as in the M2 machine gun is known as the .50 BMG - not the weapons themselves. BMG stands for "Browning Machine Gun", as the cartridge was developed for the Browning M2 machine gun.
A 50 caliber gun, or more properly, a .50 caliber gun is a firearm having an internal bore diameter of 1/2 or .50 of an inch.
American Heavy Machine Guns in WW2 fired .30 caliber rounds. The .50 caliber machine gun was 0.50 caliber which is 1/2-inch diameter and about 2 inches long. The shell before firing is about 6 inches in length.