I have been atempting to get some info on the basic data that Nikon used when developing the BDC reticle for the Omega scope. I have recieved a response from them but it included a disclaimer about not posting the info to anyone or anywhere else. So, I am not going to give out the specific info they sent me but will give my take on it and the approximate drop data it is based on. Here is what I came up with based on their info and published data.

Bullet 250 grain SST/SW
Velocity 2000 to 2100 fps
Sight In 100 yards for crosshairs
First Circle Down about 3.4"
Second Circle Down about 10.5"
Third Circle Down about 15.5"
Fourth Circle Down about 22"

All drops are averaged (based on sea level and 5000')and based on the scope being set to 9x and using the center ofeach circle for the aim point.

Their published remarks suggest 150 grains of powder and a 250 grain bullet but as we all know, every gun is different and the results are not going to always match their results. i.e. I get similar velocity to theirs using 130 grains of pellets in one of my guns.

With this basic info someone can work up an accurateload with any bullet and run a ballistic table to find the ranges for each circle for that load based on drop. Then test it at the range to verify and fine tune based on actual shooting results.Of course you can do this with any ballistic reticle scope if you know the aim point spacing.

I hope this helps clear some questions up, it did for me.