Traditional sporting bullets
Flat-nose, round-nose, and soft-point designs remain important in these cartridge families. For tubular magazines, use ammunition specifically approved by the manufacturer.
THE CARTRIDGE LIBRARY · LARGE-BORE CENTERFIRE
.50 BMG
A very large bottlenecked .50-caliber centerfire cartridge, also described as 12.7×99mm. Its rifle and military heritage is entirely separate from .50-caliber handgun cartridges.
2A Ledger reference desk · Sources checked October 18, 2026
Read the dimensions
- Overall length · max
- 5.450 in
138.430 mm - Case length · max
- 3.9098 in
99.310 mm - Bullet maximum
- 0.5110 in
12.980 mm - Rim diameter · max
- 0.8039 in
20.420 mm
Know the exact name
At a glance
- Cartridge family
- Large-bore centerfire
- Bullet specification
- 0.5110 in / 12.980 mmBullet maximum
- Factory examples
- 1 loadsSelected, sourced examples below
- Weight in cited examples
- 750 grGrains measure mass, not powder charge
.50 BMG is identified by its complete cartridge designation. The resource-table alternative is 12.7 × 99 mm. A caliber number, bullet diameter, or family resemblance on its own does not identify ammunition compatibility.
Projectile construction and military markings vary by specific loading. A painted tip is not a universal color code; use the linked identification guide.
Dimensions: open the exact dimensional drawing ↗. The displayed number is bullet maximum, rather than an assertion that every manufactured projectile or barrel has this exact diameter.
Origins & evolution
Background & development
The .50 Browning Machine Gun cartridge grew from a U.S. military requirement during World War I for a heavier machine-gun system. Winchester ammunition engineers worked with John M. Browning in 1918, and Frankford Arsenal continued the cartridge’s development. The associated prototype guns arrived too late for wartime service; the water-cooled M1921 and the later M2 followed in the postwar period.
The cartridge became a major Allied aircraft, vehicle and ground-machine-gun round during World War II. Its military identity is therefore older than the large single-shot and self-loading precision rifles with which many civilian shooters now associate it. The BMG initials preserve that original machine-gun role. Its long service history also explains the broad range of military loading designations, which describe particular projectile purposes rather than a single universal .50-caliber load. The 12.7×99 mm metric designation identifies this cartridge family, distinct from other military 12.7 mm cartridges with different cases.
Historical sources: Browning: cartridge development, Winchester and Frankford Arsenal history ↗ · Winchester: 1918 ammunition-development timeline ↗
Construction changes the story
Loads, variations & specialty offerings
Purpose-built modern loads
Flexible tips, bonded bullets, monolithic expanding bullets, and solids have different functions. A similar exterior shape or shared diameter does not establish equivalent behavior.
Firearm-specific ammunition
Some older cartridge families span firearms with very different operating limits. Keep any product restrictions with the ammunition record and use only loads authorized for that firearm.
In the cited .50 BMG examples, bullet weights are 750 grains. These are the weights actually present in this source selection, not a claim that every possible loading is listed.
Bullet construction background: Hornady: anatomy of a bullet ↗. Exact product descriptions and velocities are cited in the factory table.
From the factory catalog
750 grains
2,815 fps
A-MAX® (36" Bbl)
Compare all 1 cited factory load records
| Maker / product | Bullet mass | Published construction | Muzzle velocity | Test barrel | Source |
|---|---|---|---|---|---|
| Hornady8270 | 750 gr 48.60 g | A-MAX® (36" Bbl) | 2,815 fps 858 m/s | 36 in | Hornady · PDF p. 189 ↗ |
Explore the published data
Ballistics you can inspect
Select a legend entry to add or remove its line. Hover or tap a plotted point, or use the position slider. With the graph focused, arrow keys move the inspector. Solid dots identify source points; dashed connectors show estimates between them. Load construction, pressure category, and test setup can differ even at the same grain weight.
Read the original values as accessible tables
.50 BMG: factory velocity downrange
| Exact load | Source | Published points |
|---|---|---|
| 750 gr Hornady A-MAX® (36" Bbl) | Hornady | 0: 2815; 100: 2727; 200: 2641; 300: 2557; 400: 2474; 500: 2393 |
How to interpret the comparison
Changing bullet weight also often changes bullet design and propellant choice. Two curves are comparisons of the listed products, not a controlled experiment proving that bullet weight alone caused the difference. Catalog downrange points are projections under the maker’s conditions; barrel-study points are recorded observations in the study firearm.
Direct answers
Common questions
What is .50 BMG?
A very large bottlenecked .50-caliber centerfire cartridge, also described as 12.7×99mm. Its rifle and military heritage is entirely separate from .50-caliber handgun cartridges.
What diameter does .50 BMG use?
The cited dimensional standard lists 0.5110 inches (12.980 mm), bullet maximum. This drawing convention is different from a casual caliber nickname.
Are similarly named cartridges interchangeable?
Projectile construction and military markings vary by specific loading. A painted tip is not a universal color code; use the linked identification guide.
Are the graph values measured or estimated?
The downrange view uses the exact manufacturer catalog records shown in the source table. Dashed connectors and intermediate inspector values use linear interpolation between the displayed source points. Calculated energy uses the listed bullet mass and velocity.
Does higher energy mean the best load?
Energy is calculated from mass and velocity. It does not establish accuracy, expansion, penetration, pattern density, recoil, or suitability for a particular firearm. Use the exact product documentation and firearm manual.
Trace the facts
Sources & methodology
Compiled by 2A Ledger from the linked standards, manufacturer publications, and identified test records. Checked October 18, 2026. Historical tests and older catalogs retain their original dates; a listing here does not establish current availability.
- C.I.P.: dimensional drawing · PDF p. 1 ↗
- Hornady · PDF p. 189 ↗
- Browning: cartridge development, Winchester and Frankford Arsenal history ↗
- Winchester: 1918 ammunition-development timeline ↗
Diameter figures preserve the cited drawing convention. Inch–millimeter conversion uses exactly 25.4 mm per inch. Factory specifications describe the maker’s test setup; your firearm, ammunition lot, temperature, and measuring method can produce different results. This is an educational factory-ammunition reference, not a reloading manual.