Hello, Hello!
I haven't actually used the system but I was at the range when someone was using it. He shoots F class to 600 and said he had good luck with it. It apparently will give you corrections for elevation and angle of attack (Humidity too?) as long as your initial information was correct it should give you a spot on sight in range. No windage watsoever. It would essentially take the place of a drop chart and remembering where the scope is dialed to at the time. I was impressed with it, but it is a 3200 dollar system w/ the M4 scope (the only one that it will work on). It defenatly isn't on my short list of additions to my cabinet. Again, I never actually used it myself but I thought I'd share my two cents.