I learned at the Bang Steel Shooting school , in my second session, that shooting a 130 Grn. Bullet ay 3300 FPS out of my 270 Weatherby Mag , is not able to produce precise groups in High Wind Conditions at ranges out past 400 yards. I was unable to hit targets I had easily shot the year before , with the same rifle / scope combo but using the 150 Grn Nosler ABLR bullets, i at 3000 fps in gentle to moderate wind conditions. So speaking only for myself, If I cannot shoot 1 to 2 MOA with a high degree of confidence, due to the RANGE or the WIND or a combination of BOTH, then I must not take the shot. If I know the Rifle / Scope/ Load combo is suitable for Ex; 300 to 350 yards,( my 270 Win Ultra-light Rifle) then I have no business taking 650 to 700 yards shots with that particular set up. I believe there is a high probability of Wounding the deer, and losing it , only to have it bleed out and die later. I think knowing the true characteristics of your Hunting Set Up and YOUR personal ability to accurately and precisely control it, will require a personal sense of discipline, and confidence. I think that can be achieved, with lots of practice shooting at extended ranges. IMHO, So with the appropriate Rifle/ Scope Load Combo hitting a 24x24 inch plywood target at 900 yards, and shooting a 9 inch to 10 inch Groupe is great practice for sure, and that should be at least what I would ( personally ) expect before I would attempt to kill and Elk or Mule deer at that same range. Just my personal feeling on this issue.