Pressure effects on external ballistics

[tna9001]

Hello All,

I was playing around with the AB Analytics software and noticed that pressure uncertainty makes a big difference at distance. Is it just that as pressure decreases, aerodynamic drag decreases or is there another factor at play?

Thanks in advance!

 

[doubloon]

Humidity can play a small role at long distances.

 

[tna9001]

The first is 100% RH, and the second is 0% RH. I wonder why RH makes a difference if temperature and pressure stay constant.

 

[Slides]

The first is 100% RH, and the second is 0% RH. I wonder why RH makes a difference if temperature and pressure stay constant.

View attachment 8216233
View attachment 8216237

Water as a gas is lighter than nitrogen and oxygen for displaced volume. Large variation effects drag.

 

[Nevada Desert Rat]

The 3 things I care the most about are. Temperature, Barometric Pressure and Humility. I get out to shoot ELR several times a year for 2 weeks at a time. After hiking the course first thing in the morning. My first shot of the day is just over a mile 1790yds with my 30-06. My goal is knocking over my 12 inch wide by 18 inch tall target from a stone cold barrel first shot of the day. For me with that info it comes down to calling the wind. The wind usually wins but I get lucky enough to keep me trying.
NDR