Which environmental factors affect external ballistics computations?

Which environmental factors affect external ballistics computations?

• A. Moon phase only
• B. Temperature, humidity, and pressure affect air density and drag; adjust ballistic data accordingly.
• C. Time of day
• D. Vehicle speed.

Answer: (B)

External ballistics depends on how air density and drag influence the bullet as it travels. Temperature, humidity, and atmospheric pressure directly change air density, which in turn affects drag and the bullet’s velocity and trajectory. Colder air is denser and increases drag, warmer air is less dense and reduces drag, humidity makes air slightly less dense, and higher pressure increases density. Because these conditions vary with environment, ballistic data is adjusted to reflect the expected air density at the firing location. Moon phase doesn’t change air density in a way that’s used for these calculations, time of day isn’t a direct input to the trajectory calculations (even though it can correlate with temperature), and vehicle speed pertains to muzzle conditions rather than the atmospheric environment. So the factors that affect external ballistics computations are temperature, humidity, and pressure.

External ballistics depends on how air density and drag influence the bullet as it travels. Temperature, humidity, and atmospheric pressure directly change air density, which in turn affects drag and the bullet’s velocity and trajectory. Colder air is denser and increases drag, warmer air is less dense and reduces drag, humidity makes air slightly less dense, and higher pressure increases density. Because these conditions vary with environment, ballistic data is adjusted to reflect the expected air density at the firing location.

Moon phase doesn’t change air density in a way that’s used for these calculations, time of day isn’t a direct input to the trajectory calculations (even though it can correlate with temperature), and vehicle speed pertains to muzzle conditions rather than the atmospheric environment. So the factors that affect external ballistics computations are temperature, humidity, and pressure.