Optics Math Homework.

[advocatusdiaboli]

This is not a BDC scope but 1/2 Mildot but may work for your application. Several different magnification ranges are available. I have no idea of the quality of these scopes. http://www.eabco.com/mildotriflescopes.htm

There is also the Nikon Prostaff Rimfire 3-9x40mm with parallax set @ 50yds and a BDC reticle. Nice glass and the BDC works well. I had one and was able to shoot out to 150yds using the reticle and squirrel's head accurate for a good shooter. The Nikon website has a ballistics calculator for all their scopes and reticles which allows you to calibrate the reticle for the type of ammo that you use and it works well. You have to register to use it but no cost. You might want to try out the calculator before buying a scope to see if it works for you.