Having been a Marine and making long shots on deer after the Marines it all comes down to the scope, ammo, weapon, shooter, spotter etc....Modern scopes take into account bullet drop, windage, distance, angle of shot etc....It is not uncommon for 1 to 1.5 mile range shots for Navy seals, Marine Recon Snipers etc....Most weapons can out shoot the shooter and with modern powders, scopes and shooting a 50 caliber or equivalent it is not beyond possible......