Best of the best - Trijicon ACOG 6x48 Machine Gun Scope w/ RMR Reflex Sight

Although a bit expensive, this scope is well worth the money if the goal is to hit what you're aiming at. Additionally it is rugged and can be used in any kind of weather conditions. Coupled with the RMR all ranges are covered. This is a lifetime product and one that can be passed down through generations.