I do not know if anyone has posted this yet, but here goes my two cents…
When using Night Force / Exbal ballistic targeting software my procedure is as follows:
1)I use IMR 4831 in my .300 wm loads. That powder on average increases or decreases 2 fps per degree. Because of this, I either increase or decrease the velocity from my baseline velocity and input that sum into the data entry point of the software. I also input the current temp.
2)I input the humidity into the data entry point of the software. However, unless there is a lot of humidity in the air, it has a minor effect on the projectile. How minor? 1/10th of 1% which equals about 1/100th of an inch at 1000 yards. If there is 80% humidity or more, since it is lighter than air, it will increase the velocity of the projectile. As it is part of the equation I input it.
3)Using altitude with standard barometric pressure compared to Station pressure is a two part process.
a.I run the first part utilizing standard pressure and the current altitude. Altitude is obtained from my GPS or TOPO map. GPS is better.
b.After calculating my holds based on standard pressure and altitude, I run the equation again, only this time I uncheck the “Calculate Standard Pressure” box, and input the current station pressure obtained from my Kestrel
4000, and then run the program again.
I have found that following Gerald Perry’s instruction on this does make a difference. In any regard, Night Force / Exbal ballistic Targeting Software is a professional software package, and I recommend it highly.