FSHC = Front sight height change
SR = Sight radius
PIA = Point of impact adjustment
DTT = Distance to target
This dimension will be expressed in .000” (thousands of an
inch). This will be the amount of material to be added or
removed from the front sight blade.
If the point of impact were low then material would be removed from the front sight
If the point of impact were high material would need to be added to the front sight (or removed from the rear sight)
Sight radius is calculated from the rearward most portion of the rear sight to the rearward most portion of the top of the front sight in inches.
Point of impact adjustment is measured in inches from the center of the group shot to the point of impact desired
Distance to target.
The formula needs this dimension to be expressed in inches. Longer
distances give greater accuracy.
We use 25 yards as a standard, which is 900 inches.