Advanced Marksmanship What Standard atmosphere do you use?

[runngun]

In all my reading about density altitude (relating to shooting), the Army Standard Metro atmosphere, 29.5275 inHg, 59°F, and 78% humidity is referenced. However, Kestrel meters use the International Civil Aviation Organization (ICAO) International Standard Atmosphere (ISA) of 101.325 kPa (29.92inHG?), 15°C (59F) and 0% humidity. Also, JBM uses the ICAO ISA for its ballistic calculations.

Is there a way to change the atmospheric model on the kestrel to the Army Standard?

I guess I don't understand why shooters would use the Army Standard Metro atmosphere for ballistic calculations if the equipment measuring the density altitude is calculating a value based on the ICAO ISA.

 

[flagg888]

Re: What Standard atmosphere do you use?


That's strange and a good question.
I'm in the aviation biz and whenever I've read stuff anywhere referencing standard atmospheric conditions I've always assumed that it was refering to 29.92 and 15C at 0 humidity.
Well, I guess that's what you get for assuming.
I can't help you with your question, but I sure learned something from your question!

 

[flyboy]

Re: What Standard atmosphere do you use?

Its shouldn't matter what the standerds are as long as the readings are acurate. Any Baro/temp/humidity will give you a density alt regardless of what point on each scale is considered the zero for that persons perposes. Its is what it is. Hope that helps