### Exterior Ballistics Calculator Instructions

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The exterior ballistics calculator is designed to predict downrange point of impact based upon the diameter, ballistic coefficient and velocity of a bullet, and display the results in a numerical table and graphic form. The results can be further refined by including additional related information as defined in the calculator's input fields.

**Bullet Diameter:** Using the drop down menu, select the diameter of the bullet.

**Bullet:** We have included a list of most commonly used bullets. Using the drop down menu, select the bullet of your choice. If this bullet is not on the list, click on "No selection".

**Bullet Weight:** If you selected a bullet from the drop down list, this field will be completed. If you are working with a bullet that does not appear on the list, manually enter its weight.

**Ballistic Coefficient:** If you selected a bullet from the drop down list, this field will be completed. If you are working with a bullet that does not appear on the list, manually enter its ballistic coefficient (BC).

**Muzzle Velocity:** Enter the bullet's anticipated nuzzle velocity.

**Site Height:** This is the distance between your line of sight and the centerline of the firearm's bore. The default entry of 1.5" approximates common scope and scope mounting system heights.

**Cross wind:** Enter anticipated cross wind MPH, numerical values only. The effect of a cross wind is displayed primarily as "Drift" in calculation results.

**Firing Angle:** Uphill and downhill shooting have a significant effect on point of impact in comparison to line of sight. Enter the approximate degrees above or below the horizon. Examples, level is 0, straight up it 90, straight down is -90.

**Max. Range (yds.):** Select the maximum range you wish to see displayed. Maximum ranges between 100 and 500 yards are displayed in 50 yard increments. Ranges 600 to 1,000 yards are displayed in 100 yard increments. In all cases, calculations are in single yard increments.

**Zero Distance – Manual Selection:** Bullet typically travel in an arc compared to line of sight; the bullet will rise above the line of sight, then fall below the line of sight. Zero distance is where the bullets position and this arc and line of sight intersect. If you sight in your rifle at the range so that the bullet strikes the center of a target at 100 yards, you have established a 100 yard zero distance.

**Best Zero Distance – Auto Calculation:** Selecting a target size and leaving Zero Distance Yards at the 100 yard default will cause the calculator to select the optimal zero distance and ignore the manually entered Zero Distance Yards.

As an example, selecting a critical kill zone target size of 6” will create three tables and two graphs. Table one displays ballistic indices reflecting the entry in the Zero Distance Yards box, the second table displays the optimal zero distance and point blank range, the third table displays best zero ballistics. The two graphs are best zero trajectory and velocity.

**Calculate:** Click when entries are completed to generate tables and charts.

**Reset:** Click to clear the calculator and prepare for new entries

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