Ballistics Assistance

Ballistics Calculator HELP

Typical calculations are completed based on the norms for the Aberdeen Proving Ground in Maryland.
Altitude= Sea Level, Temperature= 59°, Barometric Pressue= 29.53 Hg, Humidity= 78%.

Input Variables

  • Firearm Type: Choose between Rifle, Rifle: Match, Rifle: Long, or Handgun
  • Description: Use this space to describe the handload or factory ammo you’re using
  • Bullet Weight: Bullet weight in grains (must be at least 10 grains up to 800 grains)
  • Muzzle Velocity: Measure in feet per second (must be between 100 and 4400 fps)
  • Ballistics Coefficient: Refer to the trajectory data. (Must be at least .001 up to 1.0)
  • Sight Height: The default height is predetermined based on the firearm type you choose (this may be changed: Range .1 to 4.0 inches)
  • Temperature: Enter in degrees Fahrenheit (Range of minus 10 degrees to 110)
  • Pressure: Enter the absolute barometric pressure for the shooting site, standard pressure is default. (Range of 20 to 35 hg)
  • Zero Range: Default is 100 yards but you can enter any value from 1 to 1000 yards
  • Wind Speed: Measured in miles per hour (Zero to 70 mph accepted)

Minute of Arc (moa)
A minute of arc, minute of angle, arcminute, or MOA is a common unit of angular measurement equal to one sixtieth (1/60) of one degree using the International System of Units definition.

This unit is commonly found in the firearms industry and literature, particularly that concerning high-powered rifles. It is popular because 1 MOA almost exactly subtends one inch at 100 yards. 100 yards or multiples thereof are traditional distances on target ranges. (The precisely-calculated value to five digits is 1.0472 inches, which is within experimental error variation from simply assuming 1 inch.) A shooter can easily readjust his or her rifle scope simply by measuring the distance in inches the bullet hole is from the desired impact point on the target, and adjusting the scope that many MOA in the opposite direction. Most target scopes designed for long distances are adjustable in quarter (1/4) or eighth (1/8) MOA "clicks". One eighth MOA is equal to approximately an eighth of an inch at 100 yards or one inch at 800 yards.

Calculating the target diameter based on minute of arc can be done using the equation: target diameter=(MOA * 2 * pi * distance)/21600. In the example previously given and substituting 3600 inches for 100 yards, (1 MOA * 2 * pi * 3600 inches)/21600 = 1.04719755 inches.

Sometimes, a firearm will be "measured" in MOA. This simply means that under ideal conditions, the gun is capable of repeatedly producing a group of shots that fit into a circle, the diameter of which can be subtended by that amount of arc. (E.g.: a "1 MOA rifle" should be capable, under ideal conditions and when locked into a vise, of shooting a 1-inch group at 100 yards.) However, ideal performance in a ballistics lab is often very different from real-world results.