Drag/Twist Input


[JBM] [Ballistics]

Instructions

Enter your data in the areas provided below. Select the "Calculate" button when all fields are filled. If the field is blank, the default (shown in brackets) is used.

Explanation of terms.

Bullet

Caliber (0.1 to 2.0 inches) [0.308]

Nose Length (caliber to 2.0 inches) [0.740]

Meplat Diameter (0.0 to half the caliber, inches) [0.062]

Ogive Radius (1 to 100 calibers) [15.0]

Nose Type [Secant]

Boattail Length (0.0 to one caliber, inches) [0.180]

Base Diameter (one caliber down to 0.1 inches) [0.251]

Total Length (1.5 to 10.0 calibers, inches) [1.464]

Rotating Band Diameter (1.0 to 1.2 calibers, inches) [0.308]

Bullet Weight (10 to 5000 grains) [210]

Bullet Specific Gravity (2.0 to 20.0) [10.7]

Drag Function [G1]

Barrel Twist (2.0 to 100.0) [10.0]


Options

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Atmosphere

Temperature (-40 to 140 degrees Fahrenheit) [59.0]

Pressure (15 to 40 inches Hg) [29.92]

Relative Humidity (0 to 100%) [0]

Altitude (-1000 to 15000 feet) [0]


Checking standard conditions at altitude cause the temperature, pressure and humidity to be adjusted for the given altitude, otherwise the air density is calculated from the temperature, pressure and humidity using the ICAO Standard Atmosphere.

Standard conditions at altitude