A fired 50 BMG at BC Firearms Academy in Vancouver.  The .50 Browning Machine Gun (.50 BMG, 12.7×99mm NATO and designated as the 50 Browning by the C.I.P.[1]) 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 a 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.

A fired 50 BMG at BC Firearms Academy in Vancouver.  Military cartridge types:

Cartridge, Caliber .50, Tracer, M1

Tracer 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, 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, 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, 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 3 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, 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 0.50 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 19mm of steel armor at 1,500 yards (1,400 m).^[10]

Cartridge, Caliber .50, Saboted Light Armor Penetrator-Tracer, M962

Like the M903, this is a Saboted Light Armor Penetrator (SLAP) round, with the only difference being that the M962 also has a tracer element for observing fire, target designation, and incendiary purposes. It uses red colored plastic sabot for identification. For use 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 effect. 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.^[11] The bullet remains supersonic out to 1,500 m (1,640 yd) to 1,600 m (1,750 yd).^[12]

Cartridge, Caliber .50, High-Explosive Armor-Piercing-Incendiary (HEIAP), Mk 211 Mod 0

A so-called “combined effects” cartridge, the Mk 211 Mod 0 High-Explosive-Incendiary-Armor-Piercing (HEIAP) cartridge contains a .30 caliber tungsten penetrator, zirconium powder, and Composition A explosive. It can be used in any .50 caliber weapon in US inventory with the exception of the M85 machine gun. Cartridge is identified by a green tip with a grey 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. The .50 Caliber MK257 is used in machine guns M2, M3, and M85. Dim trace reduces the possibility of the weapon being located during night fire and is visible with night vision devices only.^[11]

Cartridge, Caliber .50, Armor-Piercing (AP), Mk 263 Mod 2

The .50 Caliber Mk 265 has a black tip. The bullet has a hardened steel core. It is used in machine guns 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 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.^[13] It is identified by a gray over yellow tip.^[14] 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 a polymer case 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 will be applied to tracer, AP, API, and SLAP projectiles.^[15][16]

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.