How To Pick The Best Zero Range For a Load
The concept of point blank range is based on the principle that game animals have a vital zone, and placing a shot anywhere inside the vital zone does the job. Within the maximum point blank range, the shooter can aim at the center of the target's vital zone without having to hold high or low to compensate for the bullet's trajectory. This concept also works with silhouette shooting.
When you tell the program to find a load's maximum point blank range, it calculates the sight adjustment that gives the maximum zero range without the bullet ever going more than half the vital zone's size above the line of sight. The maximum point blank range is the range where the bullet finally drops more than half the vital zone's size below the line of sight. Therefore, you can aim at the center of the target and have the bullet strike within the vital zone just as long as the target is within the maximum point blank range (assuming your aim is good). However, you may have to allow for wind drift long before the target is at the maximum point blank range.
Enter the load's BC and Muzzle Vel parameters, and find your gun's current sight adjustment. Change the Find parameter to Max Pnt Blk Rng. Enter the desired value into the Vital Zone parameter. To calculate, click the Options button and then click Calc Trace Values. The sight adjustment value is now the setting needed to zero the load at the range shown in the Zeroed Rng parameter. This value is the maximum zeroed range possible without the bullet rising outside of the vital zone. Use the two sight adjustment values to determine how far and in what direction to turn your scope's elevation knob. This is covered in How To Change a Gun's Sight Adjustment.
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