Nikon Users, hearken unto me!!!!
This web-based program is pretty nifty. Here's the skinny:

If you own a Nikon brand scope, with BDC reticle (including the Mil-dot and Coyote special), and you know the loads and muzzle velocity, along with other barometric specificities, then you can calculate what range is "close" for the reticle at certain zoom notches.

http://www.nikonhunting.com/spoton


I tried a few out with my 6.8 loads I'm running, all factory loads currently, but for the most part, pretty close to where I'm hitting already. I likey!

love my buck master on my 7mm rem mag. best hunting rig ever

Love my Nikon LRT Laser rangefinder scope. Have it mounted on my M&P15T and can hit anything at 100 yrds without problem. It also have BDC on the scope. But I don't have any place further than 100 yrds to try it.