Actually if you are going with station preasure, you can ignore altitude all together. Altitude is only needed if you're using barometric pressure. If using baro, altitude is used to calculate what air pressure should be above sea level at your location which may not accuratly reflect your atmospheric condition. Station pressure is most accurate since it reports actual environmental preasure in the area the intended shot will occure. Knowing the actual preaaure, temp, and to a lesser degree humidity is far more important since this physicaly influences the projectile flight path between shooter and target no matter the altitude.
Altitude is important only if using barometric pressure. Without altitude you cant calculate preasure above sea level. Air has less density the higher the altitude becomes. Other factors that influence air density of course is temp and humidity to a lesser degree. It is the density of the air which affects drag the ballistics resolvers are looking for.
Other things that affect bullet flight over ELR shots are wind speed, wind direction, spin drift, and the coriolis effect. Then you need to input twist rate of your tube, and azimuth for coriolis, and a kestrel for wind speed. Get a kestrel with applied ballistics, and practice.
Last edited by BriGuy; 09/17/17.
