50 BMG
From left: 50 BMG, 300 Win Mag, 308 Winchester, 7.62 × 39 mm, 5.56 × 45 mm NATO, 22 Long Rifle
Type	Heavy machine gun Anti-materiel rifle
Place of origin	United States
Service history
In service	1921–present
Used by	NATO and many other countries
Wars	World War II Korean War Vietnam War Cambodian Civil War Falklands War Persian Gulf War The Troubles Global War on Terrorism Iraq War War in Afghanistan Mexican drug war Syrian Civil War Iraqi Civil War (2014–2017) Yemeni Civil War (2015–present) Saudi Arabian-led intervention in Yemen Saudi–Yemeni border conflict (2015–present)
Production history
Designer	Winchester Repeating Arms Co. and Frankford Arsenal
Specifications
Case type	Rimless, bottleneck
Bullet diameter	.510 in (13.0 mm)
Land diameter	.498 in (12.6 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)[2] 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 [1]

The 50 Browning Machine Gun (50 BMG, 12.7 × 99 mm NATO and designated as the 50 Browning by the C.I.P.^[1]) is a .50 in (12.7 mm) 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 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 made into a continuous 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.^[3]

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, and wanted the machine gun to be based on a scaled-up version of the M1917 Browning.^[4]

The development of the 50 BMG round is sometimes confused with the German 13.2 mm TuF, which was developed by Germany for an anti-tank rifle to combat British tanks during WWI and against aircraft. According to the American Rifleman: "Actually, the Browning 50 originated in the Great War. American interest in an armor-piercing cartridge was influenced by the marginal French 11 mm design, prompting U.S. Army Ordnance officers to consult Browning. They wanted a heavy projectile at 2700 feet per second (f.p.s.), but the ammunition did not exist. Browning pondered the situation and, according to his son John, replied, 'Well, the cartridge sounds pretty good to start. You make up some cartridges and we'll do some shooting.'"^[5]

The American Rifleman further explains that development was "[r]eputedly influenced by Germany's 13.2x92 mm SR (.53-cal.) anti-tank rifle" and that then "Ordnance contracted with Winchester to design a 50-cal. cartridge. Subsequently, Frankford Arsenal took over from Winchester, producing the historic 50 BMG or 12.7x99 mm cartridge. The Army then returned to John Browning for the actual gun. Teamed with Colt, he produced prototypes ready for testing and, ironically, completed them by Nov. 11, 1918—the Great War's end."^[5]

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 0.9 inches (23 mm) of face-hardened armor steel plate at 200 meters (220 yd),^[6] 1 inch (25 mm) of rolled homogeneous armor at the same range,^[7] and 0.75 inches (19 mm) at 547 yards (500 m).^[8]

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 made to withstand 12.7 mm machine gun fire, restricting 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, and 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 are ballistically similar to 50 BMGs).^{[citation needed]}

Decades later, the 50 BMG was chambered in high-powered rifles as well.^[4] The Barrett M82 50 caliber rifle and later variants were developed during the 1980s and have upgraded the anti-materiel power of the military sniper.^[4] A skilled sniper can effectively neutralize an infantry unit by eliminating several targets (soldiers or equipment) without revealing his precise location. The long range (over one mile) between firing position and target allows time for the sniper to avoid enemy retaliation by either changing positions repeatedly, or by safely retreating.

Power

A common method for understanding the actual power of a cartridge is 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, can produce muzzle energies between 2,000 and 3,000 foot-pounds force (3,000 and 4,000 J). The 50 BMG round can produce between 10,000 and 15,000 foot-pounds force (14,000 and 20,000 J), 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 cross-winds than smaller and lighter calibers, making the 50 BMG a good choice for high-powered sniper rifles.^[9]

Cartridge dimensions

The 50 BMG (12.7×99mm NATO) cartridge has a capacity of 290 gr (19 g). 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 15 in (380 mm), with eight lands and grooves. The primer type specified for this ammunition is a boxer primer that has a single centralized ignition point (US and NATO countries).^[10] 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,^[11] the U.S. Army Ammunition Data Sheets — Small Caliber Ammunition, not including plastic practice, short cased spotter, or proof/test loads, is 54,923 psi (378,680 kPa). The proof/test pressure is listed as 65,000 psi (450,000 kPa).

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. This cartridge 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 355 – 360 gr (23.00 – 23.33 g) heavy metal (tungsten) penetrator that is sabot-launched at a muzzle velocity of 4,000 ft/s (1,219 m/s). The 050 in (12.7 mm) diameter sabot is designed to separate after leaving the muzzle, releasing the 0.30 (7.62 mm) penetrator. It is injection molded of special high strength plastic and is reinforced with an aluminum insert in the base section. The cartridge is identified by an amber sabot (Ultem 1000). For use only in the M2 series of machine guns. This round can penetrate 0.75in (19 mm) of steel armor at 1,500 yards (1,400 m).^[12]

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.^[13] The bullet remains supersonic out to from 1,500 m (1,640 yd) to 1,600 m (1,750 yd).^[14]

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 US inventory with the exception of the M85 machine gun. The cartridge is identified by a green tip with a gray ring.

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 incendiary tip. It is used in the M2, M3, and M85. Dim trace reduces the possibility of the weapon being located during night fire and is visible only with night-vision devices.^[13]

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 with the Mk 211 Mod 0, but with a tracer component. This cartridge likely can be used in any 50 caliber weapon in the US inventory with the exception of the M85 machine gun, as with the Mk 211 Mod 0.

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.^[15] It is identified by a gray over yellow tip.^[16] A tracer variant of it also exists.

Cartridge, caliber 50, ball, Mk 323 Mod 0

Created by the Naval Surface Warfare Center Crane Division, this cartridge uses M33 ball projectiles in polymer cases instead of brass. It has a clear polymer case, with a standard brass head fused at the bottom. The Mk 323 can be fired from M2HB/M2A1 machine guns and GAU-21/A aircraft guns with the same performance. It gives a 25 percent weight savings over brass-cased ammunition and allows 40 percent more ammunition to be carried for the same weight. The Mk 323's polymer casing is applied to tracer, AP, API, and SLAP projectiles.^[17][18]

DARPA (Defense Advanced Research Projects Agency) contracted with Teledyne Scientific Company to develop the EXACTO program, including a 50-caliber guided bullet. Videos published by DARPA show the guided bullet diverting to strike a moving target.^{[19][20][21][22]}

Links used for feeding machine guns

Two distinct and non-compatible metallic links have been used for the 50 BMG cartridge, depending upon the machine gun which will be firing the cartridges. The M2 and M9 links, "pull-out" designs, are used in the Browning M2 and M3 machine guns.^[23][24] Pull-out cloth belts were also used at one time, but have been obsolete since 1945. The M15-series "push-through" links were used in the M85 machine gun.

Legal issues

The specified maximum diameter of an unfired 50 BMG bullet is 0.510-inch (13.0 mm); while this appears to be over the 50 inch (12.7 mm) maximum allowed for non-sporting Title I firearms under the U.S. National Firearms Act, the barrel of a 50 BMG rifle is only 50 inch (12.7 mm) across the rifling lands and slightly larger in the grooves. The oversized bullet is formed to the bore size upon firing, forming a tight seal and engaging the rifling, a mechanism which in firearm terms is known as swaging. Subject to political controversy due to the great power of the cartridge (it is the most powerful commonly available cartridge not considered a destructive device under the National Firearms Act), it remains popular among long-range shooters for its accuracy and external ballistics. While the 50 BMG round is able to deliver accurate shot placement (if match grade ammunition is used) at ranges over 1,000-yard (910 m), smaller caliber rifles produce better scores and tighter groups in 1,000-yard (910 m) competitions.^[25]

In response to legal action against the 50 BMG in the United States and Europe, an alternative chambering was developed. The .510 DTC Europ uses the same bullet, but has slightly different case dimensions. .510 DTC cases can be made by fire-forming 50 BMG cases in a .510 DTC chambered rifle. The new round has almost identical ballistics, but because of the different dimensions, rifles chambered for 50 BMG cannot fire the .510 DTC, and therefore rifles chambered for .510 DTC do not fall under many of the same legal prohibitions. Barrett offers a similar alternative, the .416 Barrett, which is based on a shortened 50 BMG case necked down to .416 caliber (10.3 mm).^{[citation needed]}

A 1999 Justice Department Office of Special Investigations briefing on 50 caliber rifle crime identified several instances of the 50 BMG being involved in criminal activities.^[26] Most of the instances of criminal activity cited in the Office of Special Investigations briefing involved the illegal possession of a 50 BMG rifle. The briefing did not identify any instance of a 50 BMG rifle being used in the commission of a murder.^{[citation needed]}

In the United States, Washington, D.C. disallows registration of 50 BMG rifles, thus rendering civilian possession unlawful.^[27][28] California prohibits the private purchase of a rifle capable of firing the 50 BMG through the 50 Caliber BMG Regulation Act of 2004.^[29] Connecticut specifically bans the Barrett 82A1 50 BMG rifle.^[30] However, 50 BMG rifles registered prior to the enacted bans remain lawful to possess in California^[28][31] and Connecticut.^[28][32] Maryland imposes additional regulations on the sale and transfer of 50 BMG rifles and other "regulated firearms", and limits purchases of any firearm within this class to one per month, but does not impose registration requirements or any form of categorical ban.^[28]

Within the United Kingdom, it is legal to own a bolt action 50 BMG rifle with a section 1 Firearms Certificate.^[33] Applications requesting firearms in this caliber are assessed by the same criteria as smaller calibers; with the applicant having to prove they have a valid reason for owning such a weapon.^[34]

Contrary to a persistent misconception within the United States Armed Forces, using 50 BMG directly against enemy personnel is not prohibited by the laws of war.^[35] Writing for the Marine Corps Gazette, Maj Hays Parks states that "No treaty language exists (either generally or specifically) to support a limitation on [the use of 50 BMG] against personnel, and its widespread, longstanding use in this role suggests that such antipersonnel employment is the customary practice of nations." Parks theorizes that the misconception originated in historical doctrine discouraging the use of the M8C spotting rifle—an integral 50-caliber aiming aid for the M40 recoilless rifle—in the antipersonnel role. This limitation was entirely tactical in nature and was intended to hide the vulnerable M40 and its crew from the enemy until the main anti-tank gun was ready for firing; however, Parks concludes that some U.S. troops assumed the existence of a legal limitation on the use of 50-caliber projectiles more generally.

On May 1, 2020, Prime Minister Justin Trudeau announced a ban on various "military-style" firearms in Canada. This ban includes firearms that chamber the 50 BMG. The ban includes a two-year amnesty period before the firearms must be surrendered, with an as-yet-unannounced compensation program in the works.^[36][37]

Typical uses

The primary military use of this round is in the Browning M2HB heavy machine gun and the Barrett M82 anti-materiel rifle.^{[citation needed]}

The U.S. Coast Guard uses 50 BMG rifles to disable outboard engines from armed helicopters during interdictions. Similarly, 50 BMG weapons have attracted attention from law enforcement agencies; they have been adopted by the New York City Police Department as well as the Pittsburgh Police. A 50 BMG round can effectively disable a vehicle when fired into the engine block. If it is necessary to breach barriers, a 50 BMG round will penetrate most commercial brick walls and concrete cinder blocks.^{[citation needed]}

The 50 BMG round has been used as a sniper round as early as the Korean War.^[38] The former record for a confirmed long-distance kill was set by U.S. Marine sniper Carlos Hathcock in 1967 during the Vietnam War, at a distance of 2,090 meters (2,290 yd; 1.30 mi);^[39] Hathcock used the 50 BMG in an M2 Browning Machine Gun equipped with a telescopic sight. This weapon was used by other snipers, and eventually purpose-built sniper rifles were developed specifically for this round.^{[citation needed]}

In June 2017, a McMillan Tac-50 was used by a sniper with Canada's Joint Task Force 2 to kill an Islamic State insurgent in Iraq, setting the world record for the longest confirmed kill shot in military history at 3,540 meters (3,870 yd; 2.20 mi).^[40] Before that record, Canadian Army Corporal Rob Furlong of the PPCLI achieved what was then the longest-range confirmed sniper kill in history when he shot a Taliban combatant at 2,430 meters (2,660 yd; 1.51 mi) during the 2002 campaign in the Afghanistan War.^[41] This was surpassed in 2009 by a British sniper in Afghanistan with 2,475 meters (2,707 yd; 1.538 mi) using a .338 Lapua Magnum (8.58×70 mm) rifle.^[42][43]

In addition to long-range and anti-materiel sniping, 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.^[44]

Some civilians use 50 caliber rifles for long-range target shooting: the US-based Fifty Caliber Shooters Association holds 50 BMG shooting matches.^[45]

Partial list of 50 BMG firearms

See also

• 50 caliber handguns
• 12 mm caliber
• 12.7×108mm (Russian equivalent)
• 14.5×114mm
• List of firearms
• List of rifle cartridges
• Table of handgun and rifle cartridges
• High Explosive Incendiary/Armor Piercing Ammunition
• .510 DTC EUROP
• .510 Whisper
• NATO EPVAT testing
• Gun laws in the United States (by state)
• 50 Caliber BMG Regulation Act of 2004

References