12.7×99mm

.50 BMG
From left: .50 BMG, 300 Win Mag, .308 Winchester, 7.62×39mm, 5.56×45mm NATO, .22 Long Rifle
Type	Machine gun/Rifle
Place of origin	United States
Service history
In service	1921–present
Used by	NATO and many others
Wars	World War II Korean War Vietnam War Cambodian Civil War Falklands War Persian Gulf War Global War on Terrorism Iraq War War in Afghanistan Syrian Civil War Iraqi Civil War (2014-present) Yemeni Civil War (2015-present) Saudi-led intervention in Yemen (2015-present) Conflict in Najran, Jizan and Asir
Production history
Designer	Winchester Repeating Arms Co. and Frankford Arsenal
Specifications
Case type	Rimless, bottleneck
Bullet diameter	.510 in (13.0 mm)
Neck diameter	.560 in (14.2 mm)
Shoulder diameter	.735 in (18.7 mm)
Base diameter	.804 in (20.4 mm)
Rim diameter	.804 in (20.4 mm)
Rim thickness	.083 in (2.1 mm)
Case length	3.91 in (99 mm)
Overall length	5.45 in (138 mm)
Case capacity	292.8 gr H2O (18.97 cm3)
Primer type	#35 Arsenal Primer
Maximum pressure (TM43-0001-27)	54,923 psi (378.68 MPa)
Maximum pressure (EPVAT)	60,481 psi (417.00 MPa)
Maximum pressure (C.I.P.)	53,664 psi (370.00 MPa)
Ballistic performance
Bullet mass/type Velocity Energy 647 gr (42 g) Speer 3,044 ft/s (928 m/s) 13,310 ft·lbf (18,050 J) 655 gr (42 g) ADI 3,029 ft/s (923 m/s) 13,350 ft·lbf (18,100 J) 700 gr (45 g) Barnes 2,978 ft/s (908 m/s) 13,971 ft·lbf (18,942 J) 750 gr (49 g) Hornady 2,820 ft/s (860 m/s) 13,241 ft·lbf (17,952 J) 800 gr (52 g) Barnes 2,895 ft/s (882 m/s) 14,895 ft·lbf (20,195 J)
Test barrel length: 45 in (1,100 mm) Source(s): Ammoguide.com

The .50 Browning Machine Gun (.50 BMG, 12.7×99mm NATO and designated as the 50 Browning by the C.I.P.) is a cartridge developed for the Browning .50 caliber machine gun in the late 1910s. Entering service officially in 1921, the round is based on a greatly scaled-up .30-06 cartridge. Under STANAG 4383, it is a standard cartridge for NATO forces as well as many non-NATO countries. The cartridge itself has been made in many variants: multiple generations of regular ball, tracer, armor-piercing (AP), incendiary, and saboted sub-caliber rounds. The rounds intended for machine guns are linked using metallic links.

The .50 BMG cartridge is also used in long-range target and anti-materiel rifles, as well as other .50-caliber machine guns.

A wide variety of ammunition is available, and the availability of match grade ammunition has increased the usefulness of .50 caliber rifles by allowing more accurate fire than lower quality rounds.

John Browning had the idea for this round during World War I in response to a need for an anti-aircraft weapon, based on a scaled-up .30-06 Springfield design, used in a machine gun based on a scaled-up M1919/M1917 design that Browning had initially developed around 1900 (but which was not adopted by the U.S. military until 1917, hence the model designation). Armor-piercing incendiary tracer (APIT) rounds were especially effective against aircraft, and the AP rounds and armor-piercing incendiary (API) rounds were excellent for destroying concrete bunkers, structures, and lighter AFVs. The API and APIT rounds left a flash, report, and smoke on contact, useful in detecting strikes on enemy targets.