Ballistic Inputs
Combining equipment, environmental, and atmospheric inputs
EQUIPMENT INPUTS
MUZZLE VELOCITY
The speed of the projectile as it exits the barrel is critical to the generation of an accurate trajectory.
TWIST RATE
The twist rate of a barrel along with exit velocity of the projectile determine its angular velocity. If this angular momentum exceeds a certain threshold, it keeps the projectile flying nose forward and the projectile is said to be stable. Blue Steel Pro computes a Miller Stability Index which needs to be at least 1.0 for stable flight (and preferably greater than 1.5).
RANGE GEOMETRY
Range to Target
Laser range finders are a very effective tool for determining the range to a target.
Inclination
Most rangefinders also display the “Look Angle”, the vertical angle of your line of sight to the target.
Target Bearing
This measurement is the compass heading of the line of sight. It can be obtained with a simple hand compass or with a mobile device that features a compass function. This input variable is needed to compute the effect on a trajectory by the spinning of the earth. This effect is called the Coriolis Force and it can be turned on or off in the user input section.
Atmospheric Inputs
TARGET BEARING
This measurement is the compass heading of the line of sight. It can be obtained with a simple hand compass or with a mobile device that features a compass function. This input variable is needed to compute the effect on a trajectory by the spinning of the earth. This effect is called the Coriolis Force and it can be turned on or off in the user input section.
AIR PRESSURE
Drag is controlled by the density of air at your location. Air density is mostly a function of your elevation and the ambient air temperature. Certain watches will give you local air pressure called “Station Pressure”, often expressed in inches of mercury (inHg). It is best if you know your Station Pressure and your local temperature and you can enter them directly. If you don’t know your station pressure, you will need to know your elevation as well as your ambient temperature and Blue Steel Pro will calculate the air density for you.
wIND
Wind often has an outsized effect on the horizontal dimension of your trajectory. Some people used handheld wind meters, but others prefer to use telltale signs of moving dust or vegetation as indirect signs of wind speed and wind direction.
HUMIDITY
Humidity only has a very small effect on the output of Blue Steel Pro. Don’t stress if you don’t know this number. You can easily get by when entering 50% for this variable.
calibration outputs
Based on your ballistic inputs, our technology delivers the most accurate scope turret adjustment settings available.
