It depends. Supposedly(non magnum) its 0at 100, top of next circle is 175, center is 200, bottom of circle is 225, between the two is 250..... and so on. Trajectory will depend alot on what wt. bullet, and at how fast. The little booklet contains all this info as well as ''tuning'' your drops...... I dunno..... I have one, but its not mounted. I trust my Burris in my 270wsm with 140 Accubonds. Its pretty darn close. But the circles in the Nikons.... I just dont know.
The only real way to find out is to shoot it and record the data under multiple conditions, and elevations. I have done this with my Burris for a couple years, and have come to know it pretty well. I got a great deal on the new Nikon, so I bought it. But..........the circles drive me nutts. I havent had the heart to mount it yet to check the actual drops. Good clear scope for the $ tho.