.50 BMG
Anti-materiel and heavy machine gun cartridge
The .50 BMG (12.7 × 99 mm NATO) is NATO’s standard heavy machine gun and anti-materiel cartridge, in service since 1921 and standardised under STANAG 4383. It is used to defeat light armoured vehicles, aircraft, boats, radars and hardened positions, and for long-range precision anti-materiel fire. Ball, armour-piercing, armour-piercing incendiary, saboted light armour penetrator and high-explosive incendiary variants are all fielded.
Full Specifications
Cartridge dimensions
| Designation | .50 BMG / .50 Browning Machine Gun / 12.7 × 99 mm NATO |
|---|---|
| Case type | Rimless, bottleneck; long case taper for feed and extraction |
| Bullet diameter | 12.98 mm (0.511 in) |
| Neck diameter | 14.22 mm (0.560 in) |
| Shoulder diameter | 18.14 mm (0.714 in) |
| Base diameter | 20.42 mm (0.804 in) |
| Rim diameter | 20.42 mm (0.804 in) |
| Case length | 99.31 mm (3.910 in) |
| Overall length | 138.43 mm (5.450 in) |
| Case capacity | 18.973 cm³ (292.80 gr H₂O) |
Ballistics
| 647 gr (42 g) | 928 m/s (3,044 ft/s), 18,050 J |
|---|---|
| 750 gr (49 g) | 860 m/s (2,820 ft/s), 17,952 J |
| 800 gr (52 g) | 882 m/s (2,895 ft/s), 20,195 J |
| Service ball reference | 890 m/s (2,910 ft/s) from a 1,143 mm barrel |
| Test barrel length | 1,143 mm (45 in) |
| Rifling twist | 380 mm (1 in 15 in), eight lands and grooves |
Standards & pressure
| SAAMI MAP | 54,923 psi (378.68 MPa) |
|---|---|
| C.I.P. Pmax | 53,664 psi (370.00 MPa) |
| Primer | #35 arsenal primer; Boxer in NATO countries, Berdan elsewhere |
| Standardisation | STANAG 4383 |
Armour penetration
| Face-hardened armour steel | 23 mm (0.9 in) at 200 m |
|---|---|
| Rolled homogeneous armour | 25 mm (1 in) at 200 m; 19 mm at 500 m |
| Saboted light armour penetrator | 19 mm of steel armour at 1,400 m |
Service context
| Introduced | Developed late 1910s, in service 1921–present, United States |
|---|---|
| Effective range | 1,800 m effective; 7,400 m maximum from a heavy machine gun |
| Common variants | Ball, AP, API, SLAP tungsten penetrator, HEIAP |
| Typical platforms | Heavy machine guns and anti-materiel rifles |
Dimensional, ballistic and pressure figures are the published C.I.P., NATO and SAAMI reference values for the .50 BMG cartridge (reference data). Steadfast production lots are proof tested and certified against the applicable standard. Product imagery is an in-house Steadfast studio visualisation and is indicative only; actual finish, headstamp and lot markings follow the applicable standard and the customer order.
