Ballistic drop / rise calculations?

While sighting in my Talon SS, I noticed significant bullet drop / rise in poa at distances.

Example: 15.8 JSB

50 ft low 3/8 inch
75 ft high 1/2 inch
100 ft high 3/4 inch

I have since zeroed the scope at 100 ft, and from my exerience here I am guessing the following:

50 ft – aim high 1.125 inches
75 ft aim high .5 inches
100 ft right on.

My current range in limited to 100 ft.

Based on this information, where is the maximum rise point and subsequent calculations for drop past that point?

And, is there a calculator to use for other weighted pellets?

Thanks!

Dan