First off, I'm new to long range shooting, I have a 100 and 400 yard range at my cabin and am having a blast shooting my 300 win mag. I have purchased a few guns in the last year, 2 Colt AR 15's, a rem 5r 300 wm, a DPMS LR-308 and a Rem. 700 sps tactical. The only one with a scope so far is the...