What are te ranges involved? If the problem is one of shooting too low then the front sight can be cut down to compensate. Here is how to figure the correction.
Example:
Range, 25 yards-------900 inches
Sight radius, 6 inches
Error, bullets strike 6 inches low
Devide the error (6 inches) by the range (900 inches)
That works out to .0066 inches.
Now
Multiply .0066 inches by the sight radius (6 inches)
The correction would be to cut down the front sight by .0396 inches, or raise the rear sight by that amount.
This works for rifles and handguns and also for figuring deflection adjustments.