Ammunition Ballistics
Computes velocity, energy, drop from the bore and the path from the line of sight at the requested distances for one load, optionally adjusted for a specific barrel length and sighting. Flown through the ICAO standard atmosphere at sea level with the G1 or G7 drag table its ballistic coefficient is stated against.
- stringheaderrequired
Your API key.
Authorization: Bearer <key>is accepted in its place.
- stringrequired
Ammunition load slug
- Accepts
- a lowercase slug: letters, digits and hyphens
- Example
- number
Barrel length to adjust muzzle velocity for
- Range
- 50 – 2000
- Example
- string
Comma-separated distances in metres
- Example
- integer
Zero distance in metres, where the bullet crosses the line of sight. Defaults to 25 for a handgun and 100 for a long gun.
- Range
- 10 – 1000
- Example
- number
Line of sight above the bore, in mm. Defaults to 20 for a handgun and 38 for a long gun.
- Range
- 0 – 150
- Example
- object
The response payload.
- object
The load the figures are for.
- string
Slug of the load the table was computed for.
- string
Display name, as the maker writes it.
- string
Slug of the cartridge. Resolve against
/v1/calibers/{id}. - number | null
Barrel length in millimetres, measured from the breech face.
- number
Muzzle velocity in metres per second, for the default load.
- number
Muzzle energy in joules, for the default load.
- number
Effective range in metres against a point target.
- TerminalBallistics
Terminal performance indices computed at the muzzle.
- number
Taylor Knock-Out factor.
- number
Momentum in kilogram-metres per second.
- number
Bullet mass divided by the square of its diameter. Higher penetrates better, all else equal.
- number
Hatcher Relative Stopping Power.
- number
Energy per unit frontal area, in joules per square centimetre.
- Zeroing
How the gun is assumed sighted for
pathCm. Neither figure is recorded per gun, so each is an assumption the caller may override withzero_mandsight_height_mm: a handgun zeroed at 25 m with its sights 20 mm above the bore, a long gun at 100 m with an optic 38 mm above it. - number
The distance at which the bullet crosses the line of sight, in m.
- number
The line of sight above the bore, in mm.
- TrajectoryPoint[]
The solution sampled at each requested distance.
- number
Distance from the muzzle in metres.
- number
Remaining velocity at this distance, in metres per second.
- number
Remaining energy at this distance, in joules.
- number
Drop below the bore line at this distance, in cm: the fall under gravity alone, with no sighting.
- number
Height relative to the line of sight at this distance, in cm, negative below: how a drop table reads, for the answer's
zeroing(the gun zeroed atzeroMwith its sightssightHeightMmabove the bore). Starts at minus the sight height at the muzzle and is 0 at the zero. - number
Time of flight to this distance, in seconds.
- number
Velocity as a multiple of the speed of sound. Below ~1.2 the projectile is transonic and destabilises.
- number
Momentum in kilogram-metres per second.
- number
Taylor Knock-Out factor at this distance.
- number
Energy per unit frontal area, in joules per square centimetre.
- 400
VALIDATION_ERRORValidation error - 401
UNAUTHORIZEDAPI key required - 403
FORBIDDENValid key, not permitted - 404
NOT_FOUNDResource not found - 429
RATE_LIMITEDRate limit exceeded - 500
INTERNAL_ERRORUnexpected server error
Requires Builder tier or higher.
If barrel_length_mm is provided, muzzle velocity is adjusted based on barrel length relative to the reference barrel.
Default distances are 0, 100, 200, 300, and 500 meters. Maximum 20 distance points per request.
Trajectory calculations use a G1 drag model with standard atmospheric conditions (15C, 1013 hPa, sea level).
- Minimum tier
- Builder+
- Monthly quota
- 25,000/mo
- Rate limit
- 60/min
- Daily cap
- 5,000
Figures shown are for this endpoint's minimum tier. Higher tiers raise every limit.