M855A1 EPR
- Cartridge
- 5.56x45mm NATO
- Bullet weight
- 4.02 g
- Reference velocity
- 961 m/s
- Muzzle energy
- 1856 J
Specification
The load, and the figures its drawing is made from
IdentityWho makes it, and what it is for.
- Designation
- M855A1
- Maker
- Various
- Country of origin
- United States
- Introduced
- 2010
- Military load
- Yes
- Widely available
- Yes
ProjectileThe figures the drawing and the solver start from.
- Bullet type
- EPR
- Cartridge
- 5.56x45mm NATO
- Bullet diameter
- 5.7 mm
- Bullet weight
- 4.02 g (62.0 gr)
- Sectional density
- 0.177
- Ballistic coefficient (G1)
- 0.307
- Ballistic coefficient (G7)
- 0.152
- Reference velocity
- 961 m/s (3153 ft/s)
- Reference barrel
- 508 mm
- Velocity retention exponent
- 0.3
Ballistics
Downrange, solved
Solved at the reference barrel of 508 mm from the G1 coefficient and the load's velocity retention. A different barrel gives a different curve.
At the muzzle
What leaves the barrel
MuzzleThe solver’s figures at the reference barrel, where the curve starts.
- Muzzle energy
- 1856 J
- Effective range
- 568 m
- Momentum
- 3.86 kg m/s
- Taylor knockout factor
- 6.3
- Hatcher relative stopping power
- 51
- Energy density
- 7274.5 J/cm²
Downrange
Point by point
The same solution as the chart, at each distance the solver reports.
| Distance | Velocity | Energy | Drop | Time of flight | Mach |
|---|---|---|---|---|---|
| 0 m | 961 m/s | 1856 J | 0 cm | 0 s | 2.80 |
| 50 m | 949 m/s | 1810 J | 1.3 cm | 0.052 s | 2.77 |
| 100 m | 937 m/s | 1765 J | 5.4 cm | 0.105 s | 2.73 |
| 200 m | 913 m/s | 1675 J | 22.4 cm | 0.214 s | 2.66 |
| 300 m | 888 m/s | 1586 J | 51.7 cm | 0.325 s | 2.59 |
| 400 m | 864 m/s | 1500 J | 94.4 cm | 0.439 s | 2.52 |
| 500 m | 839 m/s | 1414 J | 151.7 cm | 0.556 s | 2.45 |
| 600 m | 814 m/s | 1330 J | 225 cm | 0.677 s | 2.37 |
| 800 m | 761 m/s | 1164 J | 425.4 cm | 0.931 s | 2.22 |
| 1000 m | 706 m/s | 1001 J | 711 cm | 1.204 s | 2.06 |
Other loads
Other 5.56x45mm NATO loads
The same cartridge, loaded other ways.
API
The call that returns this record
The same fields, in the same units, from the same endpoint the page reads.
curl --request GET \ --url 'https://api.gunspec.io/v1/ammunition/m855a1' \ --header 'X-API-Key: your_key'