entoptics
Well-Known Member
- Joined
- Jan 16, 2018
- Messages
- 881
JBM Ballistics is a good online calculator
If you uncheck the box "Target Relative Drops" near the bottom, it will ignore your zero range, which is helpful to see the true affect of atmosphere conditions. For example, if you have a 300 yd zero input, the bullet will always have zero drop at that distance regardless of conditions, as the software is forcing it there. With "TRD" off, you will see how much actual variation in drop at a given distance for given conditions.
Increasing heat, elevation, and humidity makes the air less dense, and vice versa. Really though, humidity has a very small affect overall, so temperature and station pressure (altitude) are the important variables.
Just ran some generic numbers for 178 ELDX at roughly 30-06 speeds.
2% humidity vs 98% = ~1" more drop at 1000 yds
2000 feet vs 6000 feet = ~24" more drop at 1000 yds
60° vs 80° = ~8" more drop at 1000 yds
If you uncheck the box "Target Relative Drops" near the bottom, it will ignore your zero range, which is helpful to see the true affect of atmosphere conditions. For example, if you have a 300 yd zero input, the bullet will always have zero drop at that distance regardless of conditions, as the software is forcing it there. With "TRD" off, you will see how much actual variation in drop at a given distance for given conditions.
Also, just to be rigorous, humidity actually decreases air density (H2O is less dense than N2)....Most of the time, going up in elevation puts you in thinner, drier air, which creates less drag on the bullet.
Increasing heat, elevation, and humidity makes the air less dense, and vice versa. Really though, humidity has a very small affect overall, so temperature and station pressure (altitude) are the important variables.
Just ran some generic numbers for 178 ELDX at roughly 30-06 speeds.
2% humidity vs 98% = ~1" more drop at 1000 yds
2000 feet vs 6000 feet = ~24" more drop at 1000 yds
60° vs 80° = ~8" more drop at 1000 yds