Go to Nikonhunting.com, click on the Spot On logo, it'll take you to a site where you can enter all your load/scope data for Omega BDC scope. I have used this scope twice and I am impressed each time by the repeatable accuracy.
The Spot On site will give you the distances for each circle on the BDC reticle.
You can even generate a printable field reference ballistic chart which will give you the distances of each circle for each magnification setting on the scope. There is a BDC 250 and a BDC 300 now. Let me know what you think.
Nikon Pro Staff