I have a question, i sighted the gun in at 50 yards hitting a very nice group with nielson slugs, took the gun hunting a nice 10 point came out at 55 yards, i put the crosshairs on the normal behind the shoulder lung shot and the bullet shot over the deers back almost 6-7 inches high from where i was aiming, i knew this because i seen the dust behind him. I reloaded and aimed at the bottom of his chest and nailed him. I thought something may have came loose or something went wrong so when i got home i shot 50 yards and it was dead on. My question is do i need to sight the gun in from a tree stand or something because it hits fine from ground but high from my tree stand thats probably 30 feet high