Information in this section is accurate and very useful for customers that would like to make use of ballistic applications for smart phones as well a PC software. For top BC bullets like the VLR family this information will be most useful for distances beyond 300 meters. Although there is a small difference in weight between the two types of bullets (VLR4 vs VLR5) we found these values to be reliable and with great precision for both bullets.
The BC values for Peregrine’s VLR4 & VLR5 bullets are referenced to ICAO standards. According a definition from Wikipedia the International Civil Aviation Organisation (ICAO) published their “ICAO Standard Atmosphere” as Doc 7488-CD in 1993. It has the same model as the ISA. The ICAO Standard Atmosphere, like the ISA, does not contain water vapour.
In reality ICAO dictates that the following environmental conditions are used as a reference in the publishing of our BC values:
Ambient temperature: 15 ºC
Atmospheric pressure: 101.325 kPa (Sea Level)