Finally got a chance to shoot 500 and 1000 today. I used the gunwexrks ballistic calculators and at 1000 it was way off. For example my 7/08AI pushing a 120 ttsx at 3150 called for 20 MOA adjustment after a few rounds finally saw vapor trail hit low went to 29 MOA and scored hit. That baffles me. There was a 15 mph head wind. I am not sure if maybe my muzzle velocity was off or maybe just me but 10 Moa off seemed odd to me. New to shooting this far everything has been 500 and in prior but also noted at 500 it was a MOA off meaning called for 5 MOA and used 6. Thanks for the help