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The Caliber .50 Browning Machine Gun (BMG) Cartridge





Invented in 1918 by prolific firearms innovator John Moses Browning, the .50 BMG is the biggest cartridge available to shooters without the encumbrance of NFA restrictions, taxes, and harassment. Adopted by the US military in 1923 the .50 has endured mainstream use longer than any other cartridge in military history. (The .45 ACP, in the Browning-designed 1911 pistol is actually older, but has technically been superceded.)

Known worldwide, sometimes as the .50 Browning and sometimes as the 12.7x99 (mm) the cartridge has been used extensively in almost every conflict since its inception. Detailed History

Specifications

A note about standards

In general terms there is an accepted standard for commercially manufactured arms and ammunition. That standard, in the US, is developed by SAAMI (Sporting Arms and Ammunition Manufacturers' Institute ) and defines the specification for arms and ammunition of a given caliber. SAAMI develops standards that are implemented by ANSI (American National Standards Institute) the keepers of all US standards. The development of such standards means that when company 'x' makes a rifle for caliber 'y', that company 'z's caliber 'y' ammo will function (safely) in that rifle. Unfortunately, there is no SAAMI spec for .50 BMG (yet!). What this means is that there are multiple specs for this cartridge. There is the US military spec, various foreign military specs, and some other arbitrary specifications. I am not in the business of being a standard bearer, so I have avoided adapting any particular spec here - that is why the drawing below is noted as being 'representative'. - It is indeed within a specification, but it may not be yours! Presently there is developing a de facto specification among .50 BMG target shooters, but until it is recognized and codified as an "official" standard, there is no guarantee that your rifle or ammo are interchangeable. Until such time as a SAAMI (or equivalent) specification is adopted, the rifle to ammo relationship is the responsibility of the user. BEWARE!

Dimensions

Variations in the dimension exist, but this drawing is representative:

Projectiles

A quick guide to projectiles for the .50 BMG (I will add to these as I collect data.)
  • Projectile______Weight____BC*
  • US M33 Ball_____647_______0.670
  • US M8 API_______622.5_____0.650
  • US M20 APIT_____619_______0.650
  • Hornady A-Max___750_______1.050


    • *BC = Ballistic Coefficient

    Uses

    In a military perspective the .50 BMG is an "anti-material" round - used for destroying enemy equipment like transformers, grounded airplanes, etc.

    In civilian use the .50 BMG is used because it provides a significant challenge to the accuracy minded, participating in marksmanship exercises between 500 and 1000m. The former scarcity of the round in competitions make it uniquely challenging, as much remains to be mastered. It is also a novel cartridge for those attending machine gun shoots and other assemblies of unusual firearms.

    It should be noted that the US military has profited a great deal from civilian use and refinement of this venerable cartridge, and that without the civilian interest our convential forces would be well behind the 'power curve' that they dominate to this day.

    Myths

    I'm going to keep this more brief than it ought to be, to avoid 'preaching to the choir' about what a bunch of anti-freedom bigots have to say in their libelous campaign against this cartridge.

    The .50 BMG will reach out to extended distances. Most .50 competitions are presently held at 1000 yards, which is plenty challenging for most shooters - this is the same distance in which Marine snipers are expected to engage a man-sized target with a .308 (medium sized hunting round.) This is only slightly less challenging with a .50. The notion that the .50 BMG will enable a shooter to reach out and touch something at over a mile (1700+ yards) or more is fantasy for all but the worlds very best shooters. Even for them, these long shots are not made with anything resembling "pinpoint precision". (Incidentally, those shooters are able to achieve similar feats with standard .308 and 7mm cartridges as well.)

    The penetration of the .50 BMG has been grossly exagerated by anti-gun socialists-in-favor-of-unarmed-rape-victims. The .50 will not penetrate much more than a standard hunting rifle. (I intend to perform empirical tests and provide documentation as time permits.) An "armor piercing" round at 100 yards will just eek through 1.5" of *mild* steel (about 1/5 the hardness of low-end armor plate, or 90 Brinell vs. 500+ Brinell for Armor). This is not really astonishing, and in future tests I will compare it to the penetration of the anemic .223 and standard .308 - two other common cartridges.

    Any rifle round will go through cinder blocks ("brick walls") - I'll post evidence eventually.

    Shooting an airplane down with a single shot or semi-automatic .50 is a flight of fancy. It hasn't been done to date, and it isn't likely to occur in the future. It would take lottery-winning luck or extremely sophisticated, computer controlled, radar-guided mounts. The airplane would have to be flying low, as standard cruising altitude for commercial airplanes is around 40,000 to 60,000 feet. A military armor-piercing (AP) round fired straight up (weight 700grains, velocity =~ 2930 fps(feet per second) according to US Army FM 23-25) would only reach 15,925 ft - only about 1/3rd of the minimum required distance. It should also be noted that at that maximumum height the bullet has lost all of its energy, indeed that is the point that gravity is taking over. An effective maximum height would be *much* less. Military 'ball' ammo and competition match loads with their heavier bullets, wouldn't even reach that high.

    Drop Tables

    ---Coming Soon!---

  • M2 Ball, Muzzle Velocity = 2930fps, BC = 0.670, Zero@100yds.
  • M2 Ball, Muzzle Velocity = 2930fps, BC = 0.670, Zero@300yds.
  • M8 API/M20 APIT, Muzzle Velocity = 3050fps, BC = 0.650, Zero@100yds.
  • M8 API/M20 APIT, Muzzle Velocity = 3050fps, BC = 0.650, Zero@300yds.
  • Hornady Amax, Muzzle Velocity = 2700fps, BC = 1.050, Zero@100yds.
  • Hornady Amax, Muzzle Velocity = 2700fps, BC = 1.050, Zero@300yds.