The .50 BMG (.50 Browning Machine Gun), also known as 12.7×99mm NATO, and designated as the 50 Browning by the C.I.P., is a caliber cartridge developed for the M2 Browning heavy machine gun in the late 1910s, entering official service in 1921. Under STANAG 4383, it is a standard service cartridge for NATO forces. The cartridge itself has been made in many variants: multiple generations of regular ball, tracer, armor-piercing (AP), incendiary, and saboted sub-caliber penetrator rounds. The rounds intended for machine guns are made into a continuous ammunition belt using metallic links.
The .50 BMG cartridge is also used in anti-materiel rifles. 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.
History In response to the need for new anti-aircraft weaponry during World War I, John Browning developed the .50 BMG. He wanted the round to be used in a machine gun based on a scaled-up version of the M1917 Browning.
The development of the .50 BMG round is sometimes confused with the German 13.2 mm TuF, which Germany developed for an anti-tank rifle to combat British tanks during World War I and against aircraft. According to American Rifleman:
The American Rifleman further explains that development was:
The round was put into use in the M1921 Browning machine gun. This gun was later developed into the M2HB Browning, which, with its .50 caliber armor-piercing cartridges, went on to function as an anti-aircraft and anti-vehicular machine gun, capable of penetrating of face-hardened armor steel plate at , of rolled homogeneous armor at the same range, and at .Barnes, Frank C. (1989), "U.S. Army .50 BMG Cartridge Specifications", Cartridges of the World, DBI Books, p. 432, .
During World War II, the .50 BMG was primarily used in the M2 Browning machine gun, in both its "light barrel" aircraft mount version and the "heavy barrel" (HB) version on ground vehicles, for anti-aircraft purposes. An upgraded variant of the M2 Browning HB machine gun used during World War II is still in use today. Since the mid-1950s, some armored personnel carriers and utility vehicles have been designed to withstand 12.7 mm machine-gun fire, thereby limiting the destructive capability of the M2. It still has more penetrating power than lighter weapons such as general-purpose machine guns, though it is significantly heavier and more cumbersome to transport. Its range and accuracy, however, are superior to light machine guns when fixed on tripods. It has not been replaced as the standard caliber for Western vehicle-mounted machine guns (Soviet and CIS armored vehicles mount 12.7×108mm NSVs, which have similar dimensions to .50 BMGs).
Decades later, the .50 BMG was chambered in high-powered rifles as well. The Barrett M82 rifle was developed during the 1980s and, along with later variants, has upgraded the anti-materiel power of the military sniper.
Typical uses The primary military use of this round is in the M2 Browning machine gun and anti-materiel rifles such as the Barrett M82.
The U.S. Coast Guard uses .50 BMG rifles onboard armed helicopters to disable the engines on boats during interdictions. Similarly, .50 BMG weapons have attracted attention from law enforcement agencies; they have been adopted by the New York City Police Department and the Pittsburgh Police. A .50 BMG round can effectively disable a vehicle when fired into the engine block. A .50 BMG round will penetrate most commercial brick walls and concrete cinder blocks.
The .50 BMG round was used as a sniper round as early as the Korean War. Several world records for the longest confirmed kills were set with the .50 BMG. Eventually, purpose-built sniper rifles were developed specifically for this round.
In addition to long-range and anti-materiel, the U.S. military uses .50 BMG weapons to detonate unexploded ordnance from a safe distance. It can disable most unarmored and lightly armored vehicles.
Some civilians use .50 caliber rifles for long-range target shooting: the US-based Fifty Caliber Shooters Association holds .50 BMG shooting matches.Fifty Caliber Shooters Association, Accessed: December 10, 2022
Cartridge dimensions
The .50 BMG (12.7×99mm NATO) cartridge has a capacity of . The round is a scaled-up version of the .30-06 Springfield but uses a case wall with a long taper to facilitate feeding and extraction in various weapons.
The common rifling twist rate for this cartridge is 1 in , with eight lands and grooves. The primer type specified for this ammunition is a boxer primer with a single centralized ignition point (in the U.S. and NATO countries).NATO Infantry Weapons Standardization, Per G. Arvidsson, Chairman, Weapons & Sensors Working Group, Land Capability Group 1 - Dismounted Soldier NATO Army Armaments Group However, some other countries produce the ammunition with Berdan primers that have two flash holes.
The average chamber pressure in this round as listed in TM43-0001-27, the U.S. Army Ammunition Data Sheets — Small Caliber Ammunition, not including plastic practice, short cased spotter, or proof/test loads, is . The proof/test pressure is listed as .
Power A common method for understanding the actual power of a cartridge is the comparison of muzzle energies. The .30-06 Springfield, the standard caliber for American soldiers in both World Wars and a popular caliber amongst American hunters for medium to large game animals, can produce muzzle energies between . The .50 BMG round can produce between , depending on its powder and bullet type, as well as the weapon it is fired from. Due to the high ballistic coefficient of the bullet, the .50 BMG's trajectory also suffers less "drift" from crosswinds than smaller and lighter calibers, making the .50 BMG a good choice for high-powered sniper rifles.
Military cartridge types
The .50 BMG cartridge is also produced commercially in a wide range of specifications, including armor-piercing, tracing, and incendiary:
Cartridge, caliber .50, tracer, M1 This tracer is used for observing fire, signaling, target designation, and incendiary purposes. This bullet has a red tip. Cartridge, caliber .50, incendiary, M1 This cartridge is used against unarmored, flammable targets. The incendiary bullet has a light blue tip. Cartridge, caliber .50, ball, M2 This cartridge is used against personnel and unarmored targets. This bullet has an unpainted tip. Cartridge, caliber .50, armor-piercing (AP), M2 This cartridge is used against lightly armored vehicles, protective shelters, and personnel, and can be identified by its black tip. Cartridge, caliber .50, armor-piercing incendiary (API), M8 This cartridge is used, in place of the armor-piercing round, against armored, flammable targets. The bullet has a silver tip. Cartridge, caliber .50, tracer, M10 Tracer for observing fire, signaling, target designation, and incendiary purposes. Designed to be less intense than the M1 tracer, the M10 has an orange tip. Cartridge, caliber .50, tracer, M17 Tracer for observing fire, signaling, target designation, and incendiary purposes. Can be fired from the M82/M107 series of rifles. Cartridge, caliber .50, armor-piercing incendiary tracer (API-T), M20 This cartridge is used in place of the armor-piercing round against armored, flammable targets, with a tracer element for observation purposes. It is effectively a variant of the M8 armor-piercing incendiary with the added tracer element. Can be fired from the M82/M107 series of rifles. This bullet has a red tip with a ring of aluminum paint. Cartridge, caliber .50, tracer, headlight, M21 Tracer for use in observing fire during air-to-air combat. Designed to be more visible, the M21 is three times more brilliant than the M1 tracer. Cartridge, caliber .50, incendiary, M23 This cartridge is used against unarmored, flammable targets. The tip of the bullet is painted blue with a light blue ring. Cartridge, caliber .50, ball, M33 This cartridge is used against personnel and unarmored targets. Can be fired from the M82/M107 series of rifles. Cartridge, caliber .50, saboted light armor penetrator (SLAP), M903 This cartridge has a tungsten penetrator that is sabot-launched at a muzzle velocity of . The 0.50 in (12.7 mm) diameter sabot is designed to separate after leaving the muzzle, releasing the 0.30 in (7.62 mm) penetrator. The sabot is injection-molded from a special high-strength plastic and reinforced with an aluminum insert in the base section. The cartridge is identified by an amber sabot (Ultem 1000). Used only in the M2 series of machine guns. This round can penetrate of steel armor at . Cartridge, caliber .50, saboted light armor penetrator tracer (SLAP-T), M962 Like the M903, this is a SLAP round, with the only difference being that the M962 also has a tracer element for observing fire, target designation, and incendiary purposes. It has a red plastic sabot for identification and is used only in the M2 series of machine guns. Cartridge, caliber .50, ball, XM1022 A long-range match cartridge specifically designed for long-range work using the M107 rifle. Cartridge, caliber .50, M1022 long-range sniper The .50 caliber M1022 has an olive-green bullet coating with no tip ID coloration. The projectile is of standard ball design. It is designed for long-range sniper training and tactical use against targets that do not require armor-piercing or incendiary effects. It exhibits superior long-range accuracy and is trajectory matched to MK211 grade A. The M1022 is ideal for use in all .50 caliber bolt-action and semi-automatic sniper rifles. The bullet remains supersonic from to .Cartridges for Long-Range Sniping Rifles by Anthony G Williams
Cartridge, caliber .50, high-explosive incendiary armor-piercing (HEIAP), Mk 211 Mod 0 A "combined effects" cartridge, the Raufoss Mk 211 Mod 0 HEIAP cartridge contains a .30 caliber tungsten penetrator, zirconium powder, and Composition A explosive. It can be used in any .50-caliber weapon in the U.S. inventory, except the M85 machine gun. A green tip with a gray ring identifies the cartridge. Cartridge, caliber .50, armor-piercing incendiary dim tracer (API-DT), Mk 257 The .50 caliber Mk 257 API-DT has a purple bullet tip. The bullet has a hardened-steel core and an incendiary tip. It is used in the M2, M3, and M85. Dim tracer reduces the possibility of the weapon being located during night fire and is visible only with night-vision devices. Cartridge, caliber .50, armor-piercing (AP), Mk 263 Mod 2 The .50-caliber Mk 263 has a black tip. The bullet has a hardened-steel core and features double valleys to reduce bearing surface, thereby decreasing friction and increasing stability. It is used in the M2, M3, and M85. Cartridge, caliber .50, armor-piercing incendiary tracer (API-T), Mk 300 Mod 0 As per the Mk 211 Mod 0, but with a tracer component. Cartridge, caliber .50, armor-piercing explosive incendiary (APEI), Mk 169 Mod 2 This cartridge is used against hardened targets such as bunkers, for suppressive fire against lightly armored vehicles, and ground and aerial threat suppression. It is generally fired either from pilot-aimed aircraft-mounted guns or anti-aircraft platforms, both produced by FN Herstal. It is identified by a gray over yellow tip. A tracer variant of it also exists. Cartridge, caliber .50, ball, Mk 323 Mod 0