In about a week I'm going out with some co-workers of mine to shoot a mile. I'm bringing along my 300 Winchester Magnum. I want to give this the best chance I can making impact at that distance. I loaded up some 198gr Warner Flatlines over some H1000 last I checked was moving at 2988fps. I haven't shot this rifle past 1000 and Im not sure what to expect with shooting this far. What are some things I should take into account before attempting a shot like this? Thank you for your time. - Austin