Sunday, June 22, 2014

External Ballistics Calculations Comparison

This is a comparison of the following external ballistics calculators:
  • Gun Log (this includes Gun Log 7.1.2, Gun Log SPC 7.1.2, and Gun Log +P 7.1.2)
  • Shooter
  • Bullet Drop
Gun Log uses the standard / default values for altitude, temperature, humidity, and barometric pressure, the other  calculators allow you to enter values for those variables.

Version 7.1.3 of the Gun Log family of apps now allows you to enter altitude, temperature, humidity, and barometric pressure!

The following calculations are done with:
  • Sight Height 3.0"
  • Muzzle Velocity 2500 fps
  • Ballistic Coefficient 0.30
  • Zero Distance 100 yards
  • Wind Speed 15 mph
All of the values do not indicate the direction. Therefore the  drop value of 17.4" could be shown as -17.4 to indicate it is below the zero line. The drift values do not indicate direction either, just the amount of drift in inches. If the wind is from the right the bullet drifts to the left.

All calculators give very similar results.