LAST EDITED ON Feb-06-09 AT 04:52PM (MST)[p]I believe its a little different that what Vortex has. I've got the Vortex and love it. With factory ammo you should be able to find a bullet that closely matches all cross hairs within an inch or two if your shooting the right caliber. Keep in mind it don't work with all calibers. Works well with my 7mm Rem mag.